As the BTC and ETH prices fluctuate a lot it doesn't help for later accounting having to go back and see what the price was then to determine how much we sent and received then.
If you are looking for the accounting only, I guess there are explorer through which you can get the total sent/received value at the time of transacted, I can't remember any of the explorer which have the option to check value at the time of transacted (Will add one if I get). But if you have different invoices, in that case, I recommend Electrum as the best option for BTC. I have no idea on ETH though since I wouldn't recommend Exodus at all because of its close source code.