Endurance is no longer an issue with ssd's, at least in desktop environments. Think > 10 years in heavy usage.
The best way to install a ssd is to do a clean windows install on it.
Set the sata mode in the bios to AHCI(not ide or raid)
When loading windows do not leave your old hard drive attached or windows will try to create a hidden recovery partition on it.
If you buy a 240gb ssd, you should be able to clone your current 250gb hdd to the new ssd.
The sata mode will not be optimal, but that is a relatively minor issue.
Intel and Samsung have free clone utilities for their drives.