dude,
how often do you service the car?
if u r asking this question, seems u just got the car... so wud suggest u send it in quick, since u wud not know the service history by the previous owner...
why on earth wud u want to continue to drive it for a few weeks and send it in later? what's the difference, other than to risk expensive damage to your car? i assume u r too busy... so imagine this... during one of ur very busy days, ur car breaks down... it costs u more time and $$$ to repair. now, u got no choice but to interrupt ur schedule anyways to fix things....
so, any way u look at it, regular maintenance saves you money and time in the long run... take care of ur udm and it will take care of u... the udm is not the sort of car u can just pump gas and go... don't treat it like a japanese reliamobile...