@jba302: thanks for your thought on roi. I spared myself a detailed calculation as the best short term deposit rate you can get here is 1.5 % annually with rabodirect.
@jrhampt: Funny enough, I wanted to switch to annual payment for 3% discount with my cable tv company (unmustachian by definition, I know). They called me back to say that my €9.95 monthly rate was not valid anymore after an increase to 19.95 some years ago and they forgot to adjust my contract. The guy on the line asked me if I would still like to have a 3% discount on 19.95*12 or if I would prefer to completly cancel my request, going back to the good old 9.95 rate and everybody pretends that nothing happens. I could not believe it, of course I said "request? which request?"
Internet providers in general/Comcast in particular - did not check yet, my Internet comes through the tv cable
Gym or swim - I am with you just counted the tiles during my morning swim - of course in a public pool, no private pools for mustachians!
But be cautious with gyms, some of the chains (e.g. fitness first here in Germany and in other countries in Europe) are heavily leveraged and always on the brink of insolvency. If someone thinks he needs a gym, better pay monthly in case of doubt.
Utilities: my local public provider did not accept to switch to annual payment method. Some private electricity providers do, the actively entice clients to pay up front for a year. But we had scams and insolvencies of these providers here in Germany (teldafax) so it can be risky.
@dragoncar: thanks for you comment=> different customs in different countries, also true for payment frequency