Adverbs are used to describe a verb, adjective, or other adverb. Adverbs of frequency tell us how often something is done.

FrequencyAdverbExample
100%AlwaysI always go to the gym on Mondays.
90%UsuallyKaren is usually running late.
80%NormallyI normally work on Saturdays, but this week I don’t.
70%OftenMolly often goes for runs in the park.
50%SometimesI sometimes wear makeup, but not usually.
30%OccasionallyI occasionally go to the mall. I don’t go too often.
10%SeldomHe seldom watches the news.
5%Hardly everI hardly ever wear nail polish. I don’t like it.
0%NeverThey should never get back together.
Notice the word order: 1) subject + adverb + verb OR 2) subject + auxiliary verb + adverb

To be more specific, you can use adverbs of definite frequency.

Every + timeOnce a + time Every + number + daysTime PeriodExample
Every dayOnce a dayEvery two daysdailyI read every day.
Every weekOnce a weekEvery four weeksweeklyI wash my towels once a week.
Every monthOnce a monthEvery three monthsmonthlyI go visit my parents in New York every six months.
Every yearOnce a yearEvery five yearsyearlyI go to the doctor yearly.
Notice that these adverbs always go after the verb, often at the end of the sentence.