At that time we don't have any charts,so we should trade with the help of indicator only.....
Here's when the stop loss features become most useful, since you know the possiblity of a retraced is certain, you can always put in a stop loss at the previous all time highs and continuously increase the exit point as the trades keeps breaking new highs. This goes for all the cryptocurrency and not just for bitcoin.
With alts though you should be very cautious as what tends to follow such milestones is, traders securing their profits by cashing out which if you're not careful you'll be dumped on and since there isn't any certainty of an alts rasing again due to the numerous numbers in the industry, you might end up holding a shitcoin that has lost value.
Bitcoin on the other hands tends to increase more after previous all time high is been reached just as we saw with it breaking the $20k trading price few weeks back.
These numbers are all made up of course, I do not trade that thinly for example, my current stop loss is at 28k for example, which means it has to be a huuuuuge fall for me to get out, but I would also have a 24k and 20k big buy back after that. So you have to realize where you are going, plus I would have one at 30k in case it goes back up right away too. Stop loss is important but what you do afterwards is equally important.