Much like charylm, we have traveled for up to 10 weeks with a 24” checked bag and daypacks which are on the large side. Other than clothing, 2 pairs of shoes, meds, and personal items, I take a few things relevant to “living” since we rent self-catering accommodations. Those items include a couple of decent-but-inexpensive knives, many Ziplocs, laundry soap sheets, bag clips for resealing packages, a corkscrew and bottle stopper. Everything else we acquire locally.
As to anything you may choose to ship, ask yourself if you are also going to have to pay to ship it back to yourself.
Italy has import fees you may not be aware of. When we lived in Rome, we had shipped some clothes to the US in care of our son for a planned month-long trip involving a wedding we needed fancy clothes for. We had to cancel the trip last minute and had our son ship the suitcase back. Rather than shipping care of the US Embassy as I requested and would be duty-free, he did us a “favor” and shipped directly to our residence. For used clothes he used a value of $300 and in addition to the shipping fee, we had to pay €90.00 to Italian Customs.