The bags I want to get are
1. Givenchy Nightingale
2. Chloe Paraty
3. Balenciaga part time with giant hardware
I'm no expert on any of them but one thing I do take into consideration is whether I'm looking at a classic of the house or if it is a special of the season. I bought my Harlequin because once gone it was unlikely to come back and put off a Boston bag till another time.
I just figure if one of them may be gone by the end of the season, that may also matter to you. But again, no expert