Prices go up and down all the time.
"Supply, demand, the price of raw materials, the price of gas, location, the economy — it all affects product pricing," explains Yahoo tech columnist David Pogue in his 2016 book, "Pogue's Basics: Money."
While that's entirely out of your control, what you can control is when you shop. "In certain industries, the prices for products always drop at certain times of year, like clockwork," Pogue writes.
He provides a cheat sheet for the best time to buy just about everything, from electronics to gym memberships. Here, we've highlighted 17 essentials and the best month of the year to buy them.