I'd be disinclined to change the timing gear at half its life. One thing I would do as a 'while I'm in there' though is the hydraulic tensioner (077109479D) as this has the shortest life of all the components - particularly so on cars where the belt gets changed on age rather than mileage like most of our D2s now. I have five blown-up AVPs and that hydraulic tensioner killed two of them. The cam chain tensioner pads killed two more, and a broken valve spring did for the 5th. I've had a near-miss with the hydraulic tensioner on one other engine well before its belt interval so I always inspect that when the front end is off.
Spin the engine over by hand (clockwise) a couple of times using a bar on the crank sprocket. The belt should stay tight the whole time with no jumping about of the cam sprockets. If the cams are able to jump forwards and slacken the belt, change the tensioner.
Note - it is acceptable for the belt to be loose when the engine is stationary so don't panic if that is the case. If the engine stops in certain positions, cylinder compression can push the crank backwards which slackens the belt slightly due to the design of the tensioning mechanism (hence why its essential to never ever rotate these engines backwards). As long as the belt stays tight when its rotating clockwise then its fine
Obviously don't let the crank jump backwards when rotating by hand since that is counter-productive!
The INA branded tensioner is the genuine one with the Audi logo and number ground off, for half the price. 533003320, about £60 on ebay.
The other 'while I'm in there' job is to inspect the water pump. Check for any play in the pulley or grumbling from the bearing. Generally a genuine or good aftermarket pump will easily outlast the belt but its worth checking while its all in bits.