Either is fine, but every three weeks is more expensive. Try every four weeks, and if you have breakthrough bleeding, go to every three weeks.
No, fitness cannot be achieved by working out every two to three weeks.
Every three weeks
Sesquifortnightly. Sesqui is a prefix meaning one and a half, like in the word sesquicentennial. A fortnight is two weeks. Every three weeks, therefore, is sesquifortnightly.
every three weeks
Every three weeks at the least
Then went to the back line and had time off. A week every three weeks. Then went to the back line and had time off. A week every three weeks.
yes
every three weeks (usually drug dosing regimen)
Thomas Edison.
Thomas Edison.
There are two different kinds of years. Three out of every four years have 52 weeks and 1 extra day. Every fourth year has 52 weeks and 2 extra days. No years have 53 weeks.