I have 2" x 12" beams that make up the upstairs of my condo and was wondering what the furthest distance apart the load bearing walls that support the beams can be.

Depending on the species of wood and if they are on 16" o.c., Dougalas fir:19'-1", Hem-fir:18'-7", Sothern yellow pine: 21'-4", spruce-pine-fir: 17'10"
This is for #1 grade of these wood species. These spans are rated for attic areas & sleeping areas. (2nd floors)