Friend had a TDi Audi with an engine like my TDi Jetta. His alternator went and upon seeing the cost he did the autoparts store shuffle. The Audi and VW both use the same clutched alternator, I'd never even heard of it prior to this. He spent a ton of time swapping the thing to include having to draw down his AC system but saved a bunch! It lasted less than a month and he had to do the job again, they swapped him alternators no problem though I agree it's WAY easier on our cars and if it's not a daily it's not as big a deal but geez I hate when crap like that fails especially if you end up stranded

Edit: those of you having issues with batteries drawing down with the car sitting, have you ever swapped your ignition switch? When I swapped in a proper Bosch switch my car no longer died in days and has sat for 2-3 weeks and started easily. I DO normally tender it but when I haven't it's started fine, swapping in a new switch seems to have done it.

 

Honestly I thought there was something wrong with the car when I got it. I've never had a car that has so much drain that in about 3 weeks you have a dead battery. After asking on this site I quickly realized this is pretty normal on these cars and to trickle charger when not daily driving. So that's what I do.

If someone has some factory specs as to what the battery drain should be when the car is just sitting I'll gladly put a meter on and check it.

 

Honestly I can't figure out what goes wrong in the switches, there's nothing to them! First switch I bought was a cheapie, battery drained, I heard odd noises in the cabin key out, and the auto wipers came on with the key in my pocket. New switch solved all!

 

Pulled my Bosch out today to replace what I thought was a faulty reg, took it down to have it bench tested at rebuilder that I always use and they said it was good. Took it back home attached the + cable and was only getting 6-7 volts though it. During this I was maneuvering the alternator around and all of a sudden the cable were it mounts to the connection by the oil filter just broke off, could not have had more than 2 or 3 tiny pieces of wire still connected. New cable everything is perfect! Also replaced the diverter valves which was really easy with all that stuff out of the way.