oo ooo ooooooooo (raises hand and waves it for attention)
There are two places pinbot gets hurt. When it comes down to it, the ball does not have enough power or places to hit to cause much damage.
Flickr set for pinball where you can get bigger images.
#1. The spiral vortex ramp will be chipped like tomdotcom said. It is the top of the spiral and that part averages $125 on ebay. I have a NOS from a jackbot that I am keeping for a retirement fund

It really does not affect game play one bit, although it is a very expensive broken plastic, it is not something you can really argue over.
#2. The visor targets that move down for multiball. The orig pinbot ones are made of a plastic that shreds. Jackbot, which has the same exact part used a better plastic on the targets / switches. Also those are common switches you can order new.
#3. Besides the proper working of the visor and targets that sink into the playfield, make sure the drop targets and ramp motors work. The first piece of the ramp pops up so a target can be hit below.
If you want I can send you my phone # if you have more questions. PM me
Behind the visor expect to see a lot of damage on the playfield.