Redex is always worth doing, it dissolves the varnish and gunge that gets left behind by dinosaur fuel - I use it in Jazz and Civic every so often, but put it in my petrol mower and motorbike every tank, I used to have trouble starting my bike after it had stood unused for a while (over coldest part of winter) also bike would not tick-over very well once it had started but since having redex in petrol it starts first or second push of starter and idles well, same with petrol mower which simply would not start after standing, now it virtually leaps into life. I saw our neighbour swearing at his mower took the redex over and put some in the tank, primed it and pulled it over a few times to get petrol into carb, told him to leave it a few minutes and do it again - it started OK, and now he swears by Redex and not at his mower (it is only basically kerosene (jet engine fuel) but it dissolves stick and gungy petrol deposits) I have used it to clean carbs before.
it will keep fuel pump and injectors sweet as well.