what is the expiration date for spf?
<answer> Up to three years <context> Sunscreens are designed to remain at original strength for up to three years. This means that you can use leftover sunscreen from one year to the next. Some sunscreens include an expiration date — a date indicating when they're no longer effective. Discard sunscreen that is past its expiration date. If you buy sunscreen that doesn't have an expiration date, write the date of purchase on the bottle and be sure to throw it out within three years. Also, discard sunscreen that has any obvious changes in color or consistency.