How do you ensure that you are not paying too much for a transaction, Talking about transaction fees, how many sat/byte do you use for transactions? Do you increase and decrease it depending on how quickly you want the transaction to be processed or how big or small the transactions value is? Do you use a fixed amount for transactions?
It's best to check mempool state before sending your transaction, using websites like mempool.space is a good option, but I usually use my own BTC mempool fees browser extension.
I don't like to pay more fees than needed, but in some cases I want transaction to be confirmed faster and I use higher fees, so no it's not alwys fixed amount.
When I don't need fast confirmation I use lowest fees with RBF transaction, just in case I need to increase fee later.