I was gonna say I looked at it, then realized, who am I kidding - I mostly ignore it.
Couple of reaosns a) lender definition doesn' t match what I think DSCR is actually supposed to entail, so its not really useful when you're thinking of financing and b) it ignores cost of capital
I look at DSCR pretty early, especially if the deal depends heavily on financing. It's a good quick check on whether the property can comfortably carry the debt, but I wouldn't use it as the deciding factor. A deal can have an acceptable DSCR and still have weak cash flow once you account for realistic vacancy, maintenance, taxes, insurance, and other expenses. For me, it's one part of the underwriting, not the number that makes or breaks the deal.
honestly i buy most of my stuff at tax deed auctions so there's no lender and no DSCR to worry about. but i still think about the same underlying question which is "can the rent pay for itself with enough left over to not lose sleep?"
when i'm running numbers on a deal i basically do a rough version of it even if nobody's calling it that. rent minus vacancy, minus maintenance reserve, minus taxes and insurance. if what's left covers what the mortgage would've been with room to breathe, it's probably a decent deal. if it doesn't, then no amount of DSCR math is gonna save it.
alan's point about cost of capital is actually really good. lenders calculate DSCR with their assumptions not yours, and those assumptions can be pretty rosy. a 1.25 ratio looks comfortable until you hit a special assessment or the roof needs doing and suddenly you're feeding the property every month.
i think the useful part of DSCR is as a quick filter. if it's below 1.0 you know something's wrong. but above 1.25 it stops telling you much and you're better off just looking at actual cash flow with your own numbers plugged in.