Of course if the signs or answers were obvious in the moment, investing would be 'easy'. Rebalancing can solve a lot of these concerns. As markets go up, an investor can rebalance from equities which would become overweight in a portfolio, into something like fixed income or more defensive sectors. This on its own is likely to take a lot of the edge off of a portfolio in a strong market while allowing an investor to maintain some exposure (opposed to making a 'go to cash' type of call).
At the company level, keeping an eye on some more economically sensitive companies and seeing if they are all of a sudden missing earnings estimates or tempering their outlooks can be a good early sign that the economy might be taking a turn and you will typically see this happen at the company level before you will see it in the macro data. VIX seeing an extended rise or extreme levels for RSI could be other signals but again nothing here is a 'guaranteed' signal.
Qualitatively, when things feel a bit too 'easy' it could be a good time to sharpen one's pencil and make sure they are not over their skis. And, while it sounds cliched, the 'taxi driver pitching you a stock' signal is a sign that stocks and markets have moved to the 'front page' and any rally might be getting long in the tooth.
In terms of what inning we are in, we think markets continue to look pretty good here. North American economies are holding up and for the time being, AI investment is acting as a support to the economy. Earnings have looked solid and we see no reason to expect much in the way of surprises in the upcoming earnings season either.