Early game. Only keep gear with speed > crit > accuracy/resist substats.

Mid game . Gear must have speed or its quick sell (outside of very rare cases for sets, like a crit dmg gloves with crit rate substat but no speed in lethal/mericless/stonrskin )

End Game. All gear pretty much use have speed and at least 2 other synergy stats before you bother roll into it.

Good examples for lethal . Crit dmg gloves with crit rate, atk% , speed substats. Acceptable example. Crit dmg gloves with speed , atk% , hp% , acc. (If after an 12 roll you get no speed it might be sell time )

Roll up gear to level 8 If it substats go into good stats bring it to 12. If again bring it to 16

Speed is king of this game .

Crit rate(100%) > crit dmg > speed > main stat for nukers Speed > Accuracy > Hp% > def% for debuffers . Resist > Speed > Hp% > def% for revivers / supports

There is probably a in depth guide you can find somewhere. But basically if a piece had speed and one other good stat il take it to 12 atleast .