The upgrades, maintenance & repairs never stop. I figure something like $2000 a year for one thing or another.
The trailer running gear is always getting something. This year the center spring hangers need replacing. Already bought the replacements, holes enlarged on the old. The new are visibly more robust & will last me the rest of the time that I have the trailer. Don't know anything about welding so will have to find somebody for that. Lucky me, I do all of my maintenance in a working boatyard so no problem with the jacking up, removing wheels & all that part.
When the day comes to sell somebody will get a well upgraded albeit a well used trailer. Trouble is, all these upgrades to the running gear that we do are not understood or appreciated by they average buyer who is looking at carpet wear & fabric colours.