A lot of this depends on the specific boat, and sails being flown. A typical 22 foot, trailerable swing keel boat, equipped with a 135% to 145% genoa begins to become over powered in 12 to 15 knots of wind. If you have a 100% genoa you can extend this range upward a little bit. At the upper end of the teens, you will want to have a reef in your mainsail.
An experienced sailor could have a relatively easy time handling a typical 22 foot boat in that configuration (100%
jib and a reefed mainsail) in 20 knots of wind.
For a beginner it probably makes sense to sail in winds that are below 12 to 15 knots.
Jeff