What is my best retirement option after a mix of years in the Guard, Reserves, and active duty?

You have eight years to qualify for a Reserve 20 year letter, and another 15 years for Active Duty Retirement. You won't draw a Reserve Retirement till you are 60 years old. Use that to figure out what is best for you.

Standard answer, it depends.

It depends on your age as well as what you would do as your main job while you drill.
I recommend you sign up for a reserve component retirement brief. Government civilians can buy back their active time and count it to their federal retirement while also counting that time to their reserve retirement.

Assuming you won't be in your 50s when you become eligible for retirement, active retirement will always have a better immediate benefit.

Stay active but if you want to get out, go to the reserve component to complete that retirement.

There's a decent retirement calculator at my army benefits.gov (or something similar)

As well, are you on the new retirement program or the old one?

I've seen folks on the old one game the system, exit Active, then enter Reserve long enough just to convert their retirement cash flows into the Reserve point calculation. Maybe even pick up a promotion or two to up that pay grade calculation. But it depends on their circumstances.

Whatever you do, keep in mind the lost opportunity costs if you walk away with nothing.

There is also the cost of going reserve and getting a larger civilian pay check and being able to put more toward retirement that an Active pathway would give you, but don't walk away from what you have vested so far that can be kept in the reserves.

Remember, the reserve calculation is based on points, and one can rack up easy points here and there submitting DA1380's for on-line classes with the right chain of command and right selection of approved classes.

2020 was my best Tax year reported by the USAR (while in TPU status) and I nearly didn't step a foot in a military facility the whole year. I just racked up points every time the window opened. 15-20 extra point a year ends up being nearly an entire year of active duty added to your calculation.

The best pathway toward racking up points is sneaking in your PME while still going to AT. They come from different funding sources, and nearly both will never get denied.