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.
I always activate RBF for every transaction that uses an electrum wallet, this is important as an effort to anticipate if there is a mempool congestion. I've tried it many times so far and I find this feature very useful. However, regarding the issue of double spending or redirect a transactions to other wallets (own wallets or other people's wallets) it will certainly be a threat to anyone who makes buying and selling transactions without involving escrow, 0conf transactions allow transactions to be canceled or redirect a payment so that awareness about the possibility of a scam is needs to be improved by whoever does it. Traders need to get at least 1 confirmation to make it safe in most cases.
Thanks for explaining too, but I wouldn't do anything quite complicated unless absolutely necessary for the learning process or under certain circumstances.