Do state-based actions check in between each step of a combo or only when a player would receive priority?

State-based actions (SBAs) are checked at specific moments defined by the rules, not continuously or between every micro-step of a combo. According to CR 704.3, the game checks SBAs whenever a player would receive priority. This means they are checked after a spell or ability resolves, after a phase or step begins (before the active player gets priority), and at other defined moments — but NOT in the middle of a resolving spell or ability.

This is crucial for combos: while a single spell or ability is in the process of resolving, its instructions are followed in full before SBAs are checked and before any player receives priority (CR 608.2). So if a resolving ability causes multiple things to happen in sequence, SBAs are not checked between each sub-instruction — only after the entire ability finishes resolving.

However, if a combo involves a series of separate triggered abilities going on and off the stack, SBAs are checked between each one, because each trigger resolves individually and players receive priority in between. This can matter for creatures that might die to lethal damage or legend rule violations mid-combo.

Example: You cast a spell that says 'Create three 1/1 tokens, then deal 1 damage to each creature.' A 1/3 creature on the battlefield does not die after the first token is created — SBAs don't fire mid-resolution. Instead, after the entire spell finishes, SBAs are checked, and then the 1/3 (having taken 1 damage) survives since 1 damage doesn't kill it anyway. The point is the game waited until the spell fully resolved before checking.

Relevant rules: CR 704.3 (when SBAs are checked), CR 704.4 (SBAs are performed, then checked again until none remain), and CR 608.2 (spell/ability resolution is completed before priority is returned).