TL;DR
Use single-card proxies when the rest of your deck is already representative and you are testing one narrow substitution. Print or assemble a complete test deck when the question involves opening hands, mulligans, mana, sequencing, copy counts, sideboarding, or overall consistency. The real dividing line is not how many cards are expensive; it is whether your question concerns one card or the deck as a system.
One important refinement: “complete test deck” means a complete, randomized version of the list you intend to play. You do not need to proxy all 60 cards if you already own an accurate shell. You do need every slot—including the intended number of copies—to represent the proposed list.
When a single-card proxy makes sense
A single-card proxy is efficient when one stand-in completes an otherwise accurate deck. If you own 59 cards and want to compare the final slot between two removal spells, printing an entire deck adds work without improving the test.
This approach also works for deliberately arranged scenarios. You might place the candidate card in hand to examine whether its cost fits a particular turn, whether its rules text answers a known threat, or whether it creates the interaction you expected. That is a focused functional test, not a consistency test.
Match the proxy count to the proposed list. If the candidate would be a four-of, one physical proxy does not let you test a four-copy configuration under normal random draws. Either make four stand-ins or recognize that you are only evaluating what the card does after you deliberately introduce it.
- Use one proxy for a genuine one-slot substitution in an otherwise complete list.
- Use the intended number of proxies when testing a two-, three-, or four-copy package.
- Arrange a board state when the question concerns a specific interaction.
- Do not use a forced draw to conclude that the card appears often enough naturally.
Why a complete deck is better for consistency questions
Opening hands and draw steps sample cards from the deck without replacement, so both copy count and total deck composition determine how often a card appears. This is modeled by the hypergeometric distribution.
For example, a 60-card deck containing four copies of a card has about a 39.95% chance of finding at least one in its opening seven, before mulligans or later draws. That number describes the complete configuration. Drawing a single proxy on demand can show what the card does, but it cannot show whether four copies produce the right balance of access and redundancy.
Mana testing has the same dependency. In a 60-card deck with 24 lands, about 77.46% of opening sevens contain two to four lands; approximately 14.27% contain zero or one, while 8.28% contain five to seven. Those figures do not prove that 24 is correct for every list, but they show why the entire mana-and-spell ratio must be present when evaluating opening hands.
If mana is the problem you are diagnosing, start with the deck’s land count and colored requirements. If access to a key spell is the concern, examine how many copies of that card the deck should run before judging the card itself.
The decision by testing goal
| Testing question | Better setup | Reason |
|---|---|---|
| Does this card answer a specific threat? | Single-card proxy | You can reproduce the relevant board state and compare outcomes. |
| Should this be a one-of or a four-of? | Complete randomized deck | Natural draw frequency and redundant copies are part of the question. |
| Does the deck keep enough opening hands? | Complete randomized deck | The answer depends on the full distribution of lands, spells, colors, and costs. |
| Can the deck cast its spells on curve? | Complete randomized deck | Mana access and sequencing involve many connected slots. |
| Does this replacement feel better than the card I own? | Single-card proxy | A direct substitution isolates the changed slot. |
| Does the post-sideboard plan work? | Complete deck plus sideboard | Sideboarding changes ratios, threats, answers, and sometimes the mana curve. |
| Is an interaction legal or useful in a known position? | Single-card proxy or arranged scenario | You are testing a defined interaction rather than random access. |
Printing the full list improves test integrity
A complete test deck lets you shuffle, draw opening hands, mulligan, sequence turns, and play repeated games without deciding when the experimental card appears. That separation matters. If you know where a distinctive proxy is, the test is no longer blind.
Magic’s tournament rules require decks to be randomized so neither player knows card order or position. They also treat identifiable scratches, bends, discoloration, sleeves, or insertion differences as potential marked-card issues. Those policies govern sanctioned play rather than casual testing, but the underlying lesson applies at the kitchen table: distinguishable components can compromise random draws.
Use opaque, identical sleeves and insert every card in the same orientation. If a paper proxy is thinner than the other cards, place it in front of the same type of backing card used for the other stand-ins. Wizards has described handwritten basic lands and paper inserts placed in front of cards inside sleeves as examples of personal playtest cards used outside sanctioned events.
Players who would rather assemble a physical 60-card playtest build than prepare handwritten inserts can browse MTG proxy and playtest-card options at proxyking.biz. The purpose at this stage is repeatable testing, not collecting a polished version of a list that may change after ten games.
Do not forget the sideboard
If your format uses sideboards, a complete test deck should include the intended sideboard rather than stopping at the main deck. Constructed Magic sideboards may contain up to 15 cards under the tournament rules.
Post-sideboard games often change the deck’s internal structure. Bringing in expensive answers can raise the curve. Removing cheap threats can slow the clock. Adding narrow interaction can improve one matchup while producing weaker general-purpose draws. A main-deck-only test cannot answer whether the full match plan works.
Single-card proxies remain useful here when comparing two candidates for one sideboard slot. Once several cards move in and out together, however, test the entire post-sideboard configuration. The package—not one isolated card—is now the experiment.
A practical testing workflow
Wizards’ playtesting guidance makes the central point that theorycrafting cannot replace playing games when evaluating decisions and interactions. Its playtesting discussion supports moving from an idea to actual games rather than treating the decklist alone as proof.
- Write down the question. Examples include “Do I find blue mana by turn two?” or “Is the fourth copy useful more often than it is redundant?”
- Build the complete configuration required to answer that question. Include the intended copy counts, mana base, and relevant sideboard plan.
- Make all components physically indistinguishable from the back and through the sleeve.
- Shuffle normally, draw opening hands, and apply your actual mulligan decisions.
- Record the result that matches the question: keepable hands, missed colors, turns when the card was cast, redundant copies, or dead draws.
- Change one variable where possible. Replacing four cards and three lands at once may improve the deck, but it will not tell you which change mattered.
- After identifying the weak slot, return to focused single-card substitutions to compare likely replacements.
For a fuller build-and-revise process, use the same controlled approach described in proxying a deck before buying the real cards: test, identify a failure pattern, make a limited change, and test again.
The better default
If the deck already exists and only one slot is uncertain, start with a single-card proxy. It is faster and keeps the comparison focused. If the deck is still mostly theoretical, build the complete test list first. Otherwise, you risk judging exciting draws while missing the hands where the mana fails, the pieces arrive in the wrong order, or the sideboard plan distorts the curve.
The simplest rule is this: use the smallest proxy setup that still preserves the system you are trying to measure. A one-card question needs a one-card experiment. A deck-level question needs the whole deck.