Below I'm pasting an update of the 50 day strat val analysis for both ETH and BTC. You an see that with a 50 day look back, relative to its own risk-adjusted history we are getting quite extended here. You could almost think of this like an indicator for an over-heated engine. We don't know when it will overheat, but it is definitely getting warm.
Since I'm a hodlr, I don't sell but I do use it to help inform my buying habits. BTC is also getting up there but is not quite as over-extended as ETH. Again, these are on a risk-adjusted basis according to their own history so this is an apples to apples look.
The next charts show where we are in terms of drawdown for each. We are so close to taking out the all time highs for ETH that I would fully expect that to happen. After that, we may need to pull over to the side of the road to let the engine cool off a bit. Markets simply do not keep going up on a straight line basis.
As always, this is not investment advice and please do your own research!