I try and do more than I'm probably qualified "or knowledgeable" enough to do. I do have a bit of mechanical know how, I used to rebuild old Land rovers for a hobby, but they were easy to work on. With the bikes I tend to look at where my limitations start and end, for instance, I know I am totally crap with electrics so I leave it to the experts. Most other things I'll have a go at, if it goes wrong I can always put it in my mates van and get an expert to look at it. I do find more and more bikes and cars are becoming increasingly difficult to do things with without owning a multitude of specialist tools. That said, I also believe that "having a go" helps you get to know and understand your bike, that knowledge is especially useful if you do long distance touring, a little bit of know how can bale you out of the crap. I agree with Tiggie, you tube is brilliant, I've learnt so much on there. So I would say to anyone, if you feel comfortable having a go then do it, if not take it to a garage, I don't think it reflects on anyone as a biker.