There is nothing wrong with doing it yourself if you have the expertise and equipment available.
Removing the solenoids is tricky if you do not know how, and reflowing the solder at the dry joints can be tricky as well if you do not clean the posts.
The correct size iron of the correct wattage, solder sucker or wick and the correct solder are essential. The solenoids are not that hard to get either.
As I always say ‘How hard can it be?’