Italy is one of those places that functions differently for different people at different stages of life. The Italy of youth is urgency: the rush from Uffizi to Colosseum, the nights in hostels, the pasta at midnight. The Italy of midlife is something else. It is slower. It is more interested in the particular than the comprehensive.
The case for returning to places rather than always seeking the new is underappreciated in travel culture. But familiarity enables a different quality of attention. When you are not orienting yourself — when you know where the good coffee is — you can actually see it.
Base yourself in one place for a week rather than moving every two days. Stay somewhere with a kitchen if possible — the pleasure of shopping in an Italian market and cooking in the evening is a form of travel that no restaurant can replicate.
Learn twenty words of Italian. Not enough to have a real conversation — but enough to order with courtesy, to ask with genuine interest, to receive the small rewards of attempting to meet people in their own language.
The best thing about going back to Italy is discovering that it is not the same place you left — and neither are you.
And go in the shoulder season — October, April, early May. The Italy of September and October is Italy's Italy — and it is more interesting than the Italy of July.