I cleaned my en suite last year properly twice a month, and then just wiped the sink, brushed the loo etc. when it needed it or before I had guests.
It depends a bit on how messy you are - are you a Big Clean-er, or a Do It As You Go Along-er? It also depends on the surfaces - mine was a plastic wetroom that was really easy to clean, but a room with a "proper" floor and a bath would take longer!
In my first year I had an en suite that was cleaned by accommodation staff anyway (once a week) so you might not need to hire a cleaner. If you don't have one, it's probably not worth paying someone. Cleaning a loo is easy, bleach inside and scrub with brush, then wipe seat and lid with a cloth which you throw away immediately afterwards. I don't see why it's any worse than cleaning yourself after you do your business anyway.