Rule 3 of 31 · Chapter I — Respect the Machine
Keep guards and splitters installed
Why this rule exists
Guards get pulled off on day one and never go back on, and that's a shame, because they stop the two things that hurt people most: contact with the blade and kickback. A splitter or riving knife keeps the kerf from pinching the blade and firing the board back at your gut. Manufacturers didn't add these to slow you down. They added them because they got tired of the alternative, and so should you.
In practice
Leave the riving knife on for every cut it allows, which is nearly all of them. Use the blade guard for through-cuts, and only remove it for operations that truly require it, like non-through dados. When you do take it off, make a rule to put it back the same session, before you quit. If your saw's factory guard is genuinely awful and you fight it, buy a decent aftermarket one rather than resigning yourself to working bare.
When it doesn't apply
Some cuts, like dados, rabbets, and tenons on the table saw, physically can't be made with the guard in place. Remove it for those, use featherboards and push blocks instead, and reinstall it the moment you return to through-cuts. The riving knife often stays on even then.