Should you max out every time you long toss?
If not how often should you max out?

I have always said let your arm tell you. Some days it feels great and some days not as great. Let your arm decide.

I completely second Coach May's advice.

I would agree with Coach May and coach2709. Let your arm tell you how you feel. Bum, Jr. has alway long-tossed year-round, 5-6x week, but if he felt like not throwing a particular day, he would not.