Yes, we celebrate although we don't know the exact date. AnimalSavers told me Mitzi had been born sometime in July 2000 or 2001 so we chose the 4th of July to celebrate and she's either 3 or 4 or going on 5'ish.

Mishi we have NO idea His age at adoption was estimated at around 2 years, so he's also 4 or 5'ish, although I think he's younger or maybe just dumber, er, um I mean more cute! my silly boy! We celebrate his gotcha-date in May.