The next 24 hours may remind many of us of a simple truth: Voting is a basic right, but it can be a complicated one to exercise.

Rules vary by state and may change over time, and voters may not know them.

“Here’s what confuses people: everything,” said Daniel Diorio, an election policy specialist with the bipartisan National Conference of State Legislatures, which represents and serves state legislators and their staffs.

Polling places open at different times in different states. Here’s an easy way to check the hours in your state. (Note: Within some states, including Maine, Montana and New York, the hours vary county to county.)

About one in five voters do not know that they live in a state that requires photo identification to vote, according to a recent Pew Research Center poll. And voters in 14 states will face restrictions on Tuesday that were not in place during the last presidential election, according to the Brennan Center for Justice.