Attention Manolo, when you buy anything, note in your control spreadsheet the day, the price, the quantity, and to make it easier how much total money...

Of course, you will sell when the math result is green, but also note it in the sale.

Over time, you will have the average HODL time and the average profit obtained. If you only sell in the green, of course you will never have a loss... but please remember: the market is cyclical, it goes and comes, goes up and goes down...