i think that bigger tanks are always best if you have the room,
and you can afford to get one.
mine takes a little longer than the smaller one,but i don't mind.
many people buy second hand ones,as there are some real bagains to be had.
i feel that many fish would do better in bigger tanks,as some are very fast swimmers
and really enjoy the room.
as for my tank,i clean the water everyweekend,and test twice a month
the water readings,just because the water looks clean,does not mean that it is,
i find that problems can be got on top of,if the water is tested regularly,
in the past i kept a folder with all the information in it,i've slacked over the years.