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?
There is no surefire way to make sure you are not overpaying for the fees of each one of your transactions, your only option is to look at the mempool and see how busy the network is and see how much you need to send as a fee to get a confirmation during the next block.
However if the transaction does not need to be confirmed as fast as possible you can reduce that fee and save yourself some satoshis, but if you do this you will be taking the risk of your transaction not being confirmed for hours.