Umm don't time the market. You don't know it could go all 1990s tech bubble and hit a shiller pe of over 40. Stick to your asset allocation and move on about your life
^this +1
+2. Follow the IPS. This is exactly not the time to be switching strategies.
I'll add another 'plus' to 'stick with your asset allocation', but I'm really posting 'cuz the 'what if' comment of another tech bubble seemed troubling to me. It wasn't clear, but I think it meant -"You wouldn't want to miss out on that, would you?"
But if you start with the last 3 great years of the 90's tech bubble and go through the 3 awful years of that bubble bursting, the Total Stock Mkt lost compared to a 60/40 blend with the Total Bond Market. Add the first year of recovery from that dot com crash and both portfolios end up nearly the same place. So, missing out on a huge run up AND a following crash because shit got crazy overpriced seems totally worth missing out on.
Every boom/crash are different of course. I'm just sayin' it was an odd example to mention with an unclear point.