Yes, I regularly test the backups by restoring a random directory to my desktop and then opening a few random files to test. For things like photos which don't change (as opposed to a document which may have been edited) I'll do a quick spot-check of file hashes as well.

I'm picky about backups and have never had an issue where files were permanently lost. I'm to the point now where if I'm not sure I want a file I'll go ahead and delete it, and then if I need it later I restore from the Back In Time snapshot.

Storage is dirt cheap, so spend the time up front getting your backup 'idiot proof' and automatic and it's totally worth it in the long term.