I don't really know as im lvl 350 and don't get any exp from anything but I guess support. r we talking about kits or as well killing zombies because I saw on this server each time u kill a zombie you get say 2 bars of exp out of 10 and it means anyone get lvl up theyre exp.
When your a high lvl, when you kill a zombie, you barely get any xp,but when your under 30 xp it's not that hard getting xp i think thats why i give out my kit xp, cause it's useless when your a high lvl , so thats why i give it to other players that need it .