When will the classics leave the Southwest fleet?

I was wondering when WN will get rid of their classic series 737 aircraft. I know that allot of the classics were built in the 1990s and are not super old but aren’t they high on cycles? I was recently on a WN 737-300 from KABQ to KPHX and it was in very nice shape! I’m just curious if anyone knows when these will be retired from the WN fleet.

It depends on the economy and how Southwest feels about capacity. The -500s will be gone within the next few years, but the -300s can be kept or retired as market conditions dictate. Since things are going quite well right now it looks like the -300s will stay in service for some time.