I usually attempt to repair the item on my own if it doesn't seem very technical and save on travelling and repairing cost. I have in past was able to change my broken Samsung mobile screen. Also, I had been able to repair my room cooler after a short circuit. I had been able to root install Android software on my Alcatel tablet which was not working. I was able to change my car side mirror which got damaged in an accident.
But, there have been instance of spoiling my mobile screen also, when I tried to pull the screen. This happened to my Moto mobile. I had damaged my Sony mobile. I have even damaged my landline mobile around 20 years ago and many clock and tape recorder :).
I usually prefer getting help online as there are many platform, self help guide, videos, the only constraint that comes is the lack of specific tools. In case the tools are not expensive and they can be used again then I prefer buying them and also help myself and other at time so need. But at places where the cost of tools is high as well as the level of tech involved and well as cost of item is high I prefer going to some service shop or calling the repairing guy at my home only.
If one has little time the trying ones hand at self repair or DIY is a good option, although not recommended for all.
Knowledge is power.