The only gun I have kept is an early VA. iron mounted rifle that I built with the help of Herschel & John House. It's the 2nd gun I built & quite old and beat up looking now from all the miles it's been carried.
I've never had a problem parting with the guns I have made. Even the first gun I built, which many folks tend to have some sentimental value towards, I gladly sold...when someone offered me $1800 for it. Not to mention it is pretty rewarding to know that you can make a gun and then sell it for $3-4-5,000 or more! And then have the customer rave about it to his friends. I find it difficult to grow as a gunsmith if I have my early work sitting around in the shop. I don't want to look at the stuff, seeing the mistakes which were made (even tiny ones that nobody else seems to notice) absolutely drives me crazy. Rather than do that I just let them go and begin every rifle with the increased ability I slowly gain over time and just keep trying to "raise the bar".
If I ever am fortunate enough to build that perfect "masterpiece" of a gun, then I might like to keep it if only for the simple reason that I wouldn't have to borrow it from someone when I want to go to a show. As long as I have my old trusty beat up iron mounted gun to fill the freezer with I am set. Regards, TC