In practice, we only turn it up enough to mix in with the drummer, and the drummer dials it back in practice for our hearing protection.
I suggest you still wear ear plugs. Sound loss is cumulative. Every little bit adds up.
For practice, get some sound board(it's cheap) and put it up around the drummer. We cut a 8' piece in half and wired it together with some old clothes hanger wire.
Cleans up the band's sound a lot and cuts the noise from the drummer. Make sure it tall enough to go above the symbols.
I suggest adding more than we did. Installing some behind the drummer and hanging some from the ceiling will deaden the sound even more.
For the kick drum, cut a hole for it or mic it though the p.a. just enough for rehearsal.