Here are four things teachers should keep in mind when building their wardrobe.

Dress for physical comfort

Being uncomfortable affects everything you do—your mental processing time, your memory, and your patience with students. With this in mind, you’ll want to avoid clothes that are scratchy or constricting. Dress in layers if the temperature in your classroom is unpredictable.

Most importantly, wear comfortable shoes! You may be on your feet for seven hours—and it’s going to feel a lot longer if your feet are killing you by lunchtime.

Dress for coverage

When you’re dressing for the day as a teacher, always look at your outfit from a students’ eye view. Do you bend over desks to help students? Do you sit in a chair and read to kindergarteners? Make sure your outfits cover everything you’d want them to in each position. Also, raise your arms like you’re writing on the board and check whether your shirt still covers your back. Clothing that shows more skin than you intend to can become quite the focal point for your students.

Dress for savings and efficiency

If you’d like to avoid dry cleaning expenses or the hassle of ironing every morning, check the washing instructions of your teacher clothes before you buy them. If you’re hoping to get away with a smaller teacher wardrobe, stick with less trendy styles and low-key colors so students won’t point out (quite as often) that you wore the same thing last week.

Dress for a psychological edge

A fellow high school teacher once told me that his goal was to be featured in his school’s yearbook as the “best dressed faculty member.” I also had a colleague whose students loved her artfully chosen accessories.

All of which is to say: there may be some limits to the fashion advice you should take from me.

Teaching is an all-day performance. You need to dress so you can be “on” all day without feeling self-conscious. And that means you may need to balance your desire for efficiency with the teacher image you hope to project.

If you want to be the teacher who wears a suit, you may end up dry cleaning after all. If it’s important to you to be a trendsetter, maybe you won’t be comfortable rotating the same seven cardigans and five pairs of dark-colored pants.

And yes, ladies: if you absolutely must make a grand entrance in heels for a psychological edge, do it.

But keep a spare pair of flats in your desk drawer.