I have to admit that I have a "if it's not broken, don't fix it" mentality. The router is something that you install and if it works, it's easy to forget. I'd say that this is the main reason why I never updated it.
Regardless, it seems unlikely to me (maybe not to all of you) that it whould have been working without any problem for about 3 years, and then suddenly it needs to be rebooted every week or two. When I have some time, I'll try to apply the available updates and see if these fix anything. It would be nice if the router manufacturers would send out emails telling their customers when another update is available. This is probably the reason why many people don't update their routers - they don't know about the updates, so they just never get around to installing them.
Thanks for the pointer to the TP-Link router, and also the security tips.