That's the crux - i.e. finding the "sweet spot". You don't know the effect until you do it and then it's often too late if it doesn't work out.
Raising prices by small increments is probably not going to work as you will lose some custom, but your income/profits won't be high enough to cover the lost trade. Also, customers may accept the first time it happens, but when they return a few months later and prices have gone up again, they may not return a third time.
Raising prices by too big an amount and you could lose almost your entire customer base!
Once the damage is done, it's hard to reverse the decision. A regular customer suddenly seeing the prices rise by 25% may never return as it will force them to look elsewhere and they may find somewhere else they prefer and won't ever know that you've reduced your prices again.
Every business is different and will have a different demographic of customers so there's no "Default" sweet spot for all businesses, so changing menus, prices, opening hours, etc will always have to be a "suck it and see" thing.
With our family newsagents/convenience stores, we were open 6.5 days per week, only closed Sunday afternoons, but we closed 7pm evenings the other six days. It's easy to say we should have opened longer and on Sunday afternoons, but we tried, and tried, and tried, but there was too little custom to justify it. We trialled Sunday afternoons for an entire Summer, thinking once customers knew we were open, it would get busier, but it never did. Yes, we had money in the till on a Sunday afternoon, but we quickly noticed they were regular customers who'd have paid their weekly paper bill or bought their magazines/chocolates on Sunday morning or Monday if we'd not been open Sunday afternoon - when we started closing again, those same customers returned to coming in on other days! Classic retail "displacement". We did the same with evening opening, but same result, very little "new" customers, so we stopped again. Over the 20+ years we had it, we also trialled all kinds of different things in the shop, from a National Lottery terminal, to slush machine, to selling lots of different types of things, such as being a Xmas toy catalogue commission agent, selling models after the town's big model shop closed, commission agent for a local coach tour firm, photo developing, etc etc. Sometimes, there simply isn't enough custom/footfall to survive. As for raising prices, we once increased our newspaper delivery charge by just 5p per week and were astonished that so many customers stopped their order - for just 5p - so we had to freeze the delivery charge after that and never risked raising it again!