The difference is that the work a contracted tradesperson will do is typically under some sort of guarantee, e.g. typically 2 years on work done in your home (u

The difference is that the work a contracted tradesperson will do is typically under some sort of guarantee, e.g. typically 2 years on work done in your home (up to 5 for bigger construction etc. type work), at least here in Germany… which you don’t (need to) factor in when DIY-ing.