Yes and no. If you have used your iPhone heavy one day, and then open..let's say "BeatMaker", then a re-boot will help free some memory. Otherwise if you only use your iPhone for call, SMS and Safari, the iPhone will then not use that much of it's memory.
I have only heard positive posts about "Free Memory"!
But if you decide not to use "Free Memory" - a re-boot now and then is fine!
It's free up to 20 MB, and it has nothing to do with to many app. You're using memory when opening Safari, Mail, Games etc. Then the iPhone sometimes needs a fresh start to clear up things - that's why a re-boot or "Free Memory" will help out!
This app teaches you which other apps are memory hogs and what to do about it. Safari and the Ipod need to be shut down by holding down the home key until they go off. That stops them from running in the background and frees up much needed memory.
I didn't like this app when I first bought it. Seemed that force-closing the mail app did everything this program could do. Now (assuming it reports memory usage accurately), it seems to do an actual service in keeping the phone "fresh," even after force-closing the mail app.. I do it every so often before playing a CPU-intensive game.
It's not a "need to own" sort of app considering a <1-minute restart does the same thing, but it is more convenient for a buck.