What I do about the strategies that I need to change when it becomes unsuited for certain market conditions is that I only modify them a bit with the new good ones that I encounter I simply dissect all strategies currently available at my convenience and rebuild myself a new one combining good parts from each strategy while keeping aside the other parts in reserve so I can pull out the appropriate ones depending on the situation. And for the parts that really doesn't suit my trading style or my preferences, I just discard them to not distract myself from my current strategy. It is vital for a trader to stick to his trading strategies and plans and not get distracted with other strategies so as to avoid making clouded decisions that can eventually lead to tons of losses or missed profits.

There are several strategies that I have been keeping and still are using right now but would take forever to mention then explain since I don't just do one type of trading. So, I'll just talk about the simplest one that worked wonders for me ever since. Which is trading and holding long term on spot. How my strategy here works is buying small amounts of the coins that are suited for my standard as an investor whenever there are available funds, setting aside more funds for DCA (just in case the need for it arises), not going against the flow of the market, not getting swayed by the overexaggerated hype and lastly, sticking to my trading plan no matter what (you should at least have that much confidence in the strategy you have built before even using it) unless some unexpected REASONABLE situation arises that requires you to act otherwise.

And yes, some strategies from the past may work for certain situations in the future (at least a few parts of it if not the whole strategy) and I have proven it by experience on several occasions.

Hope this helps, good luck op.