Everyone says buy the trough. How would a beginner know they're standing in one?

I've got capital to place and no operating experience, so the whole pitch I keep getting handed is timing. National apartment vacancy around 8.5 percent, described as peaked, forecast to work back toward 7.5 percent by 2030. Values 20 to 30 percent under the 2022 peak while replacement costs are up something like 39 percent since 2020. Pipelines in Sun Belt markets contracting 40 to 50 percent. Read as a package it sounds like the bottom.

The part I can't test is the word peaked. A peak is only visible looking backward. Deliveries are still hitting the ground in some submarkets, and a market can absorb its way sideways for two years before rents actually move. If I commit in 2026 and occupancy firms in 2028, I've paid two years of a preferred return out of a property that isn't earning it yet.

The other side is real too. If I wait for four quarters of clean rent growth to print, the pricing that came with the vacancy will be gone, and so will the gap to replacement cost that made the entry basis interesting in the first place.

So what would you actually accept as evidence? I'm not asking what the forecast says. I'm asking which observable number you'd want to see move before you sign a subscription document. Definitions welcome, I'm new to this and half of these terms I've only read, never used.