When do you cut your losses?

At what point do you accept that one of your coins might never recover, or you may never make back your losses? I'm not talking about selling BTC during a dip. I'm talking about selling a coin you bought at its ATH, that tanked with no hope of recovery. (I'm looking at you ICP) When do you roll over whatever you have left into another investment or a stable? Years? Months?

I'm a perma-holder; I never sell anything to a fault. I'm in it long term, ten years or more, so in my head, I think, "Oh, it can get back up to its ATH by 2030", but that might not be the best way to preserve capital. At best, it's "dead" money; at worst, it drops further in value and never recovers. I read something like, "Although hope has its place in theology, it does not belong in the cold, hard reality of investing."

I also think taking the hit would be better for tax purposes to offset capital gains. But again, I'm still holding some things with the idea that they could recover at some point.

One of the most enduring sayings is "Cut your losses short and let your winners run."

When do you cut your losses?