I typically go to options for each module and set the period to the last period for each year and then do a period end for each year (2015, 2016, 2017 …)

As BL indicated, monthly periods tend to be no big deal as long as it isn't a legacy module.  However if you are on SQL you shouldn't have any legacy modules.

...or have the customer / user do all the period end's themselves as penance / training.  If they haven't been doing monthly reconciliations (AR to GL, AP to GL, IM to GL...) that is not good, from an accounting perspective.

Technically, upgrades are not affected by period end.  (Payroll may be different).

lol

Well we ended up doing a few last night and the month ends didn't take too long, but 2015 YE took over 90 min. I think the plan is to do a few every night until she is caught up. I don't know how they are doing reconciliations, but they have good accountants. At least that's what I'm told. I can handle basic accounting, but this company is quite complex for a small business, so a lot of it goes right over my head.

Well we ended up doing a few last night and the month ends didn't take too long, but 2015 YE took over 90 min. I think the plan is to do a few every night until she is caught up. I don't know how they are doing reconciliations, but they have good accountants. At least that's what I'm told. I can handle basic accounting, but this company is quite complex for a small business, so a lot of it goes right over my head.

Change the "Years to Retain" settings to be higher (module by module), and the year end processing should go more quickly.  History data purges take time.