I think in some older version of WinRar once the 40 days were up you could still extract archives but it wouldn't let you create any. Now it does everything even after you time is up, you just get the nag screen.
I've had my copied registered for many years now. I like to support the people who make the software I use.
I also registered Winzip many, many, many years ago. At the time I registered I was told free upgrades for life. Then when version 10 came out they said you had to pay to get the upgrade. I haven't used it since. I don't mind paying again but don't sell something with a promise of free upgrades for life when you don't mean it.