Well, let's say your installed route on your desktop has a kuid of 2:XXXX:25001:1. Your laptop has that route installed so you can work on it while riding the local roller coaster, and you have made many changes. So Open for edit in explorer and change the kuid to 2:XXXX:25001:2. When you take that out and put it on your desktop it should overwrite/obsolete kuid 2:XXXX:25001:1. The you work on it on your desktop, finish, save and the Open For Edit in Explorer and change the kuid to kuid 2:XXXX:25001:3. Then when you take that to your laptop and install, it should overwrite and obsolete kuid 2:XXXX:25001:2. Then when you....I think you get the idea. Or, you can as Oknotsen has suggested.
Actually, the more backups, the better, so I think deleting old versions is a small price to pay!