If you were to open a restaurant, what are the key concerns? Quantify them for Chulhavik Dining's Rs 1.5 crore, 80-seat outlet at 1.5 and at 2.5 table turns a day, and say which risk matters most.

Footfall is the risk that decides it: payback is about 22 months at 1.5 turns and about 8 months at 2.5. Each diner leaves Rs 469 after food cost, against Rs 10 lakh of fixed cost a month, so the outlet breaks even at 0.89 turns. Monthly profit is Rs 6.88 lakh at 1.5 turns and Rs 18.14 lakh at 2.5. Rent matters far less: 50% more rent costs Rs 2 lakh a month.

A restaurant has the same shape as a cinema or a gym: a big cost to open, a fixed bill every month, and a margin on every customer who walks in. So the concerns sort into three numbers: what it costs to open, what it costs to keep the doors open, and how many people come through them. Everything else on the usual list, the chef, the menu, the location, the licences, matters because it moves one of those three numbers. An interviewer who asks about key concerns is checking whether you can turn a list into that structure and then rank it.

Each diner pays Rs 700 and food costs 33% of that, so each cover leaves Rs 469 to pay for rent, staff and everything else. The fixed bill is Rs 4 lakh of rent plus Rs 6 lakh of staff and running costs, Rs 10 lakh a month. Dividing Rs 10 lakh by Rs 469 gives 2,132 covers a month, or 71 a day. With 80 seats that is 0.89 turns a day just to break even.

At 1.5 turns the outlet serves 3,600 covers a month, Rs 25.2 lakh of revenue. Food costs Rs 8.32 lakh and the fixed bill Rs 10 lakh, leaving Rs 6.88 lakh a month, so the Rs 1.5 crore fit-out pays back in about 22 months. At 2.5 turns it serves 6,000 covers, Rs 42 lakh of revenue, and keeps Rs 18.14 lakh: payback in about 8 months. The same outlet, same rent and same menu is either a two-year bet or an eight-month one.

Rent feels like the big risk because it is fixed and signed for years. But a 50% rent rise costs Rs 2 lakh a month. One table turn a day is 2,400 covers a month at Rs 469 each, about Rs 11.3 lakh, so footfall moves profit more than five times as much as a large rent shock. That is the operating-leverage point: once the fixed bill is covered at 0.89 turns, nearly half of every extra rupee of revenue falls to profit. The flip side is just as steep. At 1 turn a day the outlet makes only Rs 1.26 lakh a month and needs 10 years to pay back.

Ask for turns by outlet, by weekday and weekend, and by outlet age, not the founder's chain average. A new outlet that sits at 1.5 turns for its first six months burns most of a year of the payback clock before it reaches plan. Then check the second-order costs this sketch leaves out: delivery aggregator commissions if delivery is part of the plan, wage inflation, and the deposit and rent-free period on the lease. The limit of the exercise is that it treats 1.5 and 2.5 as given. The real diligence is finding out which one this location will deliver, from the chain's existing outlets in similar streets.