Precious battery treatment?

[VONDUTCH]

Well you guys seem to be such a treasure trove of info and advice thought I'd give it another go.
What's the deal with the charging and discharging of Ni-Mh batteries? I've not yet met anyone or read anywhere the reasons behind their precious treatment. Are modified motors so wild that they cannot last 5-6 mins offroad-in my limited experience this is not true.We get 4000mah batteries and use perhaps half that and then discharge the rest only to recharge them again-I thought Ni-Mh had no memory and that was one of their advantages?
I realize I'm only a beginner but I use my 3300mah for at least 2 if not 3 heats (bargain ) Now I will admit that's in a stock motored,low geared 2wd buggy but it still seems to fly in the face of what I see most other people doing???
I'm unemployed and on a tight budget but I'm sure I'm not the only one so what's the best factually correct advice on the treatment of batteries.Surely it can't just be about a case full of cells,specialised discharge trays,pc link ups and extreme priced chargers.
Hope this isn't too much to ask Thanks guys ahead of any help