What pressure to leave fully-carbed keg at

I kegged my first brew a couple weeks ago. I used BeerSmith to calculate the proper CO2 volume and the pressure needed for the temp of the chamber. I ended up with 13 PSI @ 44 degrees F for a 2.4 Volume of CO2 (Style was American Amber). After about a week at 13 PSI, the beer was well carbed. I had to turn down the PSI to about 5 to serve through a 5 foot picnic tap to prevent foaming.

The question is, now that the beer is fully carbed, do I leave the pressure at serving PSI? or should it be back up at 13? if I leave it up at 13, do I risk over carbing?

You really need longer beer line as you should really leave the beer at the correct psi and not have to fiddle around to serve. 10' of beer line is not very expensive. But in your current situation you do need to maintain psi @ 13 or it will eventually equalize down to 5.

OK, that makes sense. I was thinking I would need longer lines eventually, but until I get them, good to know that I'll want to keep the carb up except when I'm serving (which is what I've been doing).

Thanks for the info.