Yes. Every your memory goes below, oh say 20 (just to be on the safe side) I'd do a battery pull. I look at my memory once a day just to make sure. I can usually go 4-5 days withouht doing a battery pull. The reason why I'm responding is cuz my phone is doing a hard reset now when I had 29 megs free.
So still, I don't wanna lose anything so I do a pull when it gets below 30. It's a 6 minute process to reboot, but hey ... I used to pull the storms every day :P So the addded time is less than the storms over 4-5 days xD hehe.