FileVault on or off?

I just discovered that I have an encryption option (FireVault). It's off by default. Should I turn it on? I left it off because I don't want it to slow things down. I assume it does, but I don't know. I'm pretty sure there is nothing worth unearthing on this computer, so under what circumstances do people generally enable it?

Oops, yes,I misspelled FileVault in the title!

There's a slight performance hit (see here) but nothing that should be all that much of a problem. Here, however, are some other things to consider.

My advice: if you don't need it, keep it disabled. If you have a notebook (MBA or MBP), it might be worth looking into if you're concerned about theft.

For me, whole disk encryption is a condition of use for work . The performance hit is, really it is, minor.

If you don't care about any of the data on your computer, then leave it off.