I did this for a few years and would recommend 1 (smallish) suitcase + 1 backpack.

As mentioned in the article, it’s better (financially and socially) to stay in locations for a medium length of time. If you do this, then the overhead of a single suitcase is very minimal, and you get far more flexibility with clothing - particularly if you’re staying in colder areas. E.g. NYC in winter.