The reason you sort laundry is to prevent damage by incorrectly sorted laundry. The basics are by type of soil/dirt or grease. All pieces of clothe in a wash load should require the same temperature, wash time and use of bleach. Cottons requires 10-12 minutes of wash time, synthetics require 7-9 minutes & only 3-4 minutes for delicates or wool.

Recommended color groupings:

Whites, and white background prints that are colorfast.

Non-colorfast colors typically dark colors.

Level of soil, heavily soiled and lightly soiled should not be mixed.

Texture types, lint producers like towels, flannel etc. should not be mixed with synthetics or permanent press type items which will attract lint.