RBF in general? Loads of times. RBF to essentially cancel a payment and send coins somewhere else? Only once or twice since I'm generally very careful about where and when I send bitcoin and I don't often encounter a scenario when I would want to redirect a payment to an entirely different address.

How to do it will depend on the wallet software you use. Some, such as Electrum, give you options to bump the fee or "cancel" the transaction by double spending it back to your own wallet, but if you want to do something more complicated than that then you'll need to delete the transaction from your wallet and create a brand new one from scratch or use an external tool to create a transaction to import in to Electrum for signing.