Banks are generally open weekdays 9 to 3. In Puerto Vallarta most are open until 4, and some of the larger banks keep a few branches open Saturday from 9 or 10 to 1 or 2:30; however, the extended hours are often for deposits or check cashing only. HSBC is the one chain that stays open for longer hours; on weekdays they are open 8 to 7 and on Saturday from 8 to 3. Government offices are usually open to the public weekdays 9 to 3; along with banks and most private offices, they're closed on national holidays.
Gas stations are normally open 7 AM-10 PM daily. Those near major thoroughfares stay open 24 hours, including most holidays.
Pharmacies are usually open daily 9 AM to 10 PM; on Sunday and in some small towns they may close several hours earlier. Puerto Vallarta has some 24-hour pharmacies: look for the big names such as Farmacias del Ahorro or Farmacia Guadalajara. In neighborhoods or smaller towns where there are no 24-hour drug stores, local pharmacies take turns staying open 24 hours so that there's usually at least one open on any given night -- it's called the farmacia de turno. Information about late-night pharmacies is published in the daily newspaper, but the staff at your hotel should be able to help you find an all-night place.
Stores are generally open weekdays and Saturday from 9 or 10 AM to 2 or 3 PM; in resort areas, those stores geared to tourists may stay open until 9 or 10 at night, all day on Saturday; some are open on Sunday as well, but it's good to call ahead before making a special trip. Some more traditional shops close for a two-hour lunch break, roughly 2-4. Airport shops are open seven days a week.