How exciting, NK! I'm happy for you! You and Emily seem to share about the same sort of relationship that Selash and I do. We're pretty new to this whole shebang too.
See what the subs on these forums will do to you switches? *giggles*
I've left one (bullet) in all night, few hours, but on a low setting. I haven't had any problems with desensitization. But I'm with tessa, better to start slow with a few minutes than start big with a few hours.