Does everyone on progestin only pulls experience breakthrough bleeding ? if so how long does it last ?

This is probably the most common side effect in progesterone only pills it is a little less common in progesterone injections like Depo-Provera. It will vary across-the-board with regards to how long it will last. I generally tell patients that if it occurs in more than 2 to 3 cycles we may need to reevaluate and change pills

The most reported side effect of progestin-only pills is breakthrough bleeding (irregular bleeding or spotting). Depending on the type of progestin-only pill taken, the first 3-4 months is when breakthrough bleeding most often occurs but will likely go away with time. If a pill is taken late or missed, then that could also contribute to irregular bleeding.