Time limit for Phone's auto lock?

Hey guys,

Since some of you asked me to increase the phone's auto lock time to about 10 minutes, it's been done but I am still unsure whether to keep it or not as if you leave your handset without locking it, it will drain your battery fast enough thus locking it always is the only option and a necessity to somehow.

So what do you reckon guys, should I keep it as a feature or set it to it's maximum value as 5 minutes.