Hey Hawkeye. Changing the computers is totally based on your type of business. I always suggest that you don’t spend the money unless you need to.
If your computers are fulfilling the customers needs then invest elsewhere. Make sure you have a good software such as virus and malware scanners or programs that people may want to use. Add secondary sales items or services if you have the money to invest.
If you are thinking of adding gaming and Esports then make sure your computers can handle extra performance requirements. If the computers are older and lower on specs (such as RAM, graphics cards or processor speed) then upgrade for sure. Nothing says you have to do all the computers at the same time. Gauge demand first the add more as the need is there. The computers in gaming centers need to be good. Nothing is more frustrating as competing on a computer that cannot keep up.
Every business is different so you need to take a look at yours. As long as the customer is happy with the way your computers are running and their information is safe, then your computers are ok. If you plan to expand to other services then upgrade.