I have just had a hard lesson in why not to delay getting things serviced. I'd known my chain needed to be replaced in the near future for about a month, but I'd re-tensioned it and it had been fine for the time being. Yesterday though, I saw that it was really quite loose and I could hear it chattering when taking off. With that in mind, this morning I rang my local bike mechanic and booked it in to get done this coming thursday. Not having a car available today, and not wanting to sit on a couple of busses for 90 minutes each way, I rode it to my girlfriends place this morning, and then at 5 pm I came back. No troubles still. About 30 minutes ago my dad was going out, and asked me to move the bike so he could get his car out of the garage. Normally I park leaving room but I was lazy and didn't know he was going out. Our driveway is on a small but steepish slope and since I needed the keys to unlock the steering I started it up so I could drive back up. As I was taking off it bogged down a whole bunch and I heard the chain come off. The sudden jerk with which it happened made me loose my balance and the only reason I didn't drop the bike was because I'm pretty sure I've put my back out holding it up. So, I came very close to dropping my bike and/or crushing my left foot, I've put my back out and now I can't ride all week.More importantly than that it is only dumb luck that it happened outside my house and not while riding home. If it had happened while I was in one of the 80 zones I pass through it could have been very, very bad. All because I was lazy. So, take heed of this advice and don't learn the hard way like I have. If something needs fixing do it ASAP.