Man, you better get used to ID'ing stuff.
Also, most stuff in the early game isn't lethal enough that you can't risk using them right away.
In crawl, any potion or scroll you have found 4 or five copies of below level 7 or something similar, is mostly safe to blindly use. Do it when YOU ARE NOT IN A PINCH and you should do fine.
Nethack is less forgiving for that.