Is the Non-O visa multi-entry and how does it compare to the Non-OA visa for retirement in Thailand?

I have had both non imm oa and o extension based on retirement ...overall, particularly if you already have 800k in a thai account I found the o retirement extension option both easier to get and overall cheaper due to less certificates and insurances. Particularly as you pass age 65 and insurance premiums rise steeply often.

U can get 1year non o multiple entry but must leave the country at least every 90days (borderrun)

Assuming that NI is short for Non-immigrant:

1. The Non-O Visa based on being over 50 is NOT multiple entry. This visa allows you to stay in Thailand for 90 days, and allows one entry. If you want to leave Thailand and return, you will need to get a re-entry permit, which keeps your "admitted to" stamp "alive" when you leave. This visa is cheaper to acquire at the local consultant, and *MIGHT NOT* require a police report or special health insurance.

2. The Non-OA visa based on being over 50 *IS* multiple entry. On each entry, you are stamped in for one year, or the length of your health insurance, whichever one is less. This requires more paperwork including a criminal background check, must be issued from the Thai consulate of your passport (i.e. if you're holding a British passport, the Thai consulate of London), and requires medical insurance. IF you acquire a One Year Extension of Stay based on being over 50, you will need health insurance.