At the end of 2017 my company announced that we were going from a bi-weekly pay schedule to a semi-monthly pay schedule. This means that instead of payday being every other Friday, it will be every 15 days, unless it falls on a weekend or holiday (or something like that, it's really dumb). So you can see that the pay date, although usually falling on the 5th or 20th, varies. Sometimes it's a Tuesday, sometimes it's a Thursday, sometimes there are three weekends between paydays. And the pay period isn't always going to be the same number of work days. For instance, one of my paychecks in February had only nine work days so my paycheck was smaller than usual.
This may not seem like a big deal to some, but for a planner like me, it is extreeeeemely frustrating. The lack of consistency in days and paychecks makes me feel like I'm going to short circuit. But alas, despite the feedback from employees, I don't think it's going to change. So until then, I'll just refer to chart they provided and wait not-so-patiently for my pay stub to become available to budget off of.