Most branded or quality ceiling fans are designed to run 24/7 without giving you any problem. So rest assured if you leave your ceiling fan running for the whole day nothing will go wrong. The only thing is, your electrical bill will just go up slightly without you noticing it.
The Marketplace doesn't have any built-in payment mechanism, so you have to arrange payments directly with the other party in a transaction. Reputable Marketplace traders will welcome the use of secure services, which benefits legit buyers and sellers alike. Avoid transactions that don't involve local buyers/sellers.