If you mean weapons and such like ... there is no point in using a weapon above your level. To use a weapon effectively (and hit anything like the scatter range shown) you must have sufficient experience/weapon skill (p/s, s/s, ranged) i.e. equal to the level of the weapon.

KmS

how about armor?

Never tried armour, don't think you get any protection if it's too high a level for you (the armour must be the same as your character experience level).

That's right. Stu the best thing you can do is stick to weapons and armor that are your level. I'm not sure if there's a certain percentage for the non-effectiveness of a higher- level weapon, but I DO know its a greatly reduced number. 
for example: you buy a dracosteel mace, level 28 s/s, max hit 230-ish.

But if you have a level 10 character to use the mace, damage could go from 230 to 15 or some crazy thing. So just buy stuff your level.

for protection stu use the diamond mail shirt (if you 
can get the 25k needed) it will last you all the first 20  lvls

Mad

X-(