I was looking at the owners manual for my Colt AR-15 today. I was thinking about the thread The "Wet" AR and wanted to see what the manual says. I think it takes about a dozen drops of oil to do everything except the bore.
Anyway, in the back of the manual is my purchase date in 1987. It was $576 new from my co-worker who was a part-time dealer. It will be 21 & 1/2 years old next Tuesday. If it was a person it could drink and vote and drive a car. It's only needed a few things in all that time, like a set of gas rings.
Time flies when you don't know what you're doing. I've had my Ruger 10/22 since the late '70s when I was in high school. 1978 I think. It was $63 or $67 IIRC, and that's with a $150 real walnut stock. I'll have to dig out the receipt later. It's needed a little work over the years too. I replaced the barrel once. The firing pin too.
I tend to buy a gun I want, keep it, and never trade it in. Are you celebrating a 10th anniversary, 20th birthday, or anything else for your old guns?