I have an old cornet that bought on ebay a few years ago. It had broken braces and some misalignment in the tubing in some places. The instrument repair person at Riverton Music in Sandy, Utah repaired it. He did a good job.

There were also some minor dents in a couple of places. I fixed those myself, or perhaps I should say I reduced the dents to smaller dents. I used steel balls and a strong magnet, with the tubing taped to avoid scratches. It took a long time and gave me tennis elbow of my right arm which has taken more than a year to mostly heal, so I think it was not a good idea to do that repair myself.

By the way, the instrument repair person at Riverton Music is a woodwind player. He told me something interesting. He learned to play several woodwinds as a career move. Of course, being a multi-instrumentalist gave him a wider variety of gigs for which he was qualified, but he told me that the main reason he became a multi-instrumentalist is because he gets paid more for a given gig, even if he only uses one instrument. It has something to do with how the fees are structured, maybe something to do with the musicians union, I don't know, but anyway he gets paid more that way.