OK, I already know from various postings (e.g."I can't imagine staying in La Spezia in order to have firm reservations" near CT) that when we are in Italy and CT for the first time 2-3 weeks from now, we should just show up in Riomaggiore or Vernazza and ask about available rooms, thus enjoy the CT nightfall and daybreak, etc.
However: we will be arriving from a way too brief (24hrs) stay in Siena by train (3hr) at La Spezia, likely near or after DARK (it's March, not May). All the next day's daylight would be devoted to exploring CT by trails/train, unless some sort of wet/cold weather intervenes. The following morning needs an early departure to make good use of the days of our 2 nights reserved in Florence (followed by 2 nights Venice).
In this CT scenario, 2 nights at a La Spezia hotel seems to at least serve as a place to leave ourselves free of whatever luggage while to/in/from CT. Of course I'd prefer to someday overnight in CT with time to linger, but arriving late (family hour? daylight gone?) seems to diminish the possiblities, no? I suppose if we happened upon a room at either end of CT during our 'CT day' we could fetch our bags (from LaSpezia station?) to have one CT night ..but I'd guess 'downtown' La Spezia is more likely to have affordable cafe choices after dark on night two, and lessen the odds of reaching Florence much later than intended.