It depends how much you use it. Modern super unleaded goes off quite quickly, so they need regular fresh fuel in them. If you have an early car with a metal fuel tank, condensation can form and the precisely machined metal parts of the fuel injection system don't take too kindly to the moisture if they are left sitting for long periods. Wurth fuel cure is good for laid up cars.
Some injector cleaner is good to use as part of every service tho'. One dose in no more that 20 litres of fuel to give it a good strong mix.