Solved Category customports

If I make an own port, I had it add to the category/Makefile. But this could be overwritten with the next update.
If I make an own category I had it add to /usr/ports/Mk/ under VALID_CATEGORIES. But this could also overwritten. (If I don't edit the Makefiles there are error messages from portmaster(8),synth(1), etc.)
Is it considerable to make general a category customports or overlooked I something?
It might depend how to update. I have switched from portsnap to the svn method. Just a few days ago I have made a port comms/statserial which still resides in the ports tree. The motivation was Thread 55037 and the curiosity to see how it works. It survives svnlite up. I have it elsewhere, too. I put it in my ports tree just to test it with devel/poudriere.
I don't like svn(1) very much. On one box I have svn(1), on all other I work wirh portsnap(8).
I think it will be practical, if there were a "official" category customports (and it is surely no problem to make this).
Btw, I have scripts to handle this, but this is not the simple way, could be easier.