Should I use my OPT or STEM OPT first, or switch to Day 1 CPT now?

If you still have OPT or a STEM OPT extension you can use, it usually makes sense to use it first - Day 1 CPT is the backup for when your OPT is ending, your unemployment days are running out, or the lottery didn't work. Keep the limits in mind: 90 unemployment days on OPT (150 in total with a STEM extension), and a STEM extension needs a STEM degree and an E-Verify employer. Tell me your OPT end date and I'll map when a backup needs to start.