The first thing I look at with any New Jersey laundromat is the lease. Buyers and lenders usually want ten or more years left, including options. A great store on a short lease is a hard sell, so before you fall in love with the machines, read the lease.
Next is equipment age. Ask how old most of the washers and dryers are, and what's been replaced recently. A store with newer machines costs more up front but usually needs less work in the first years you own it.
Then utilities and the real numbers. Water, gas and electric tell you a lot about how the store actually runs, and the books tell you whether the revenue is steady. If the seller can't show you real numbers, walk slowly.
Finally, look at the extras: wash and fold, pickup and delivery, commercial accounts, card or app payments. These are where a good store becomes a better one.
If you're hunting in New Jersey, tell me your budget and the towns you want. When an owner who fits is ready to sell, you'll hear from me.