Whatever your grading and attendance policies, make sure they’re printed in a distributed syllabus - even if it’s just online. This way you have guidelines (outlined from day one) that you can hold to. Also, include language that states that exceptions are rarely made, but the instructor ultimately reserves the right to adjust accordingly.
My attendance policy typically allows a set number of absences with no correspondence or excuse required (big time saver). Further absences dock percentages off of their total grade, and beyond those (at some higher and set number) they automatically fail the course.
Typically, I allow a week’s worth of free absences, but this feels too harsh when there’s only one meeting a week - so I adjust it. I’ve never had complaints about this because I choose numbers that are fair, doable, and they’re outlined from the start. Someone almost always fails out on attendance, but how can I pass someone who misses a total of three or four weeks of class - including all the work during those absences?
I don’t accept late work, but I gladly accept early work. My assignments are always available in advance, so a student who decides to use a free skip day can still get all their points if they turn their work in at or before the due date. It’s easy to get swamped in grading late work, and the policy of “I’ll just grade it whenever you can get it into me” undermines any sense of a deadline. Again, this is laid out in the syllabus, so it’s clear from day one.
Finally, on the subject of grades, don’t approach grading as a grade that you give; grading is the grade that they earn. As long as you’re process is fair and transparent across the board, you shouldn’t have any problems.
All of this likely sounds harsh and like the nightmare prof, but I’m actually the relaxed, funny, and easy to get along with instructor in my classes. I don’t “lay down the law” the first day, I just meet my students with respect and openness. “This is who I am, and this is how the course will be run for everyone.”