On the other hand, imagine if you start what you think is going to be a simple job such as changing a bottom bracket, of which I have done a few. Then you run into unexpected problems, and find that it is going to take a lot more expertise, time and tools than you have got, as I did recently. I'd already bought a new bottom bracket. I normally fix everything myself, and was resistant to the idea of going to a bike shop.
I took it to a couple of bike shops, the first thought it was beyond them, the second obligingly took it on and fixed it very quickly.
So, saving money is one thing, and you definitely learn by doing, but sometimes you have to consider letting someone with more facilities and expertise do the work. The hard part is, knowing where to draw the line, when to let go. My local independent car garage will fit parts or even tyres that I've bought off the internet, I don't see the harm in asking your bike shop to do the same. It's all income for them after all, at worst they can only say no.