If you vape it or ingest it for OA pain, I assume you are doing it in the day and could get distracted by the high. Was your multi-day relief from a large dose or just a few tokes? Did you have to get high for pain relief? By the way, I have nothing against getting high but I don't like the idea of needing to get high when I would not otherwise want to in order to fight pain.
If you're in a state where MMJ is legal, you can purchase high CBD strains that have a high ratio of the compounds that give pain relief, but are low on the stuff that makes you high (the THC). I haven't tried these yet but apparently, they give pain relief without making you high.
As for me, I am very new to this, disregarding my dabbling many years ago
Because I haven't yet determined whether I'll be doing it on a semi-regular basis, I have not yet invested in a vaporizer, choosing to roll joints and smoke it that way. However, if I decide to do it at least semi-regularly, I'll either use edibles, or a vaporizer, and will probably go for the high CDB stuff. Like you, I don't have anything against getting high occasionally, just as I like the occasional beer or glass of wine. I don't like it when it begins to take away from my productivity or enjoyment of life though. While I don't think a few tokes on a joint is going to do much to my long term health, I don't want to use that method going forward if I decide to do it on anything other than an extremely occasional basis.
Two tokes is my maximum. The high lasts a few hours, but the pain relief seems to last for a few days. The fact that my osteoarthritis is at an early stage probably helps too, so not much is needed. I have read that the high from vaping is less intense, so even with a strain that has moderate amounts of THC, I'm thinking that one toke with a vaporizer might give a pleasantly agreeable mild high, combined with the needed pain relief. Alternatively, a high CBD strain is always a possibility.
If my rambling answer wasn't clear, my multi-day pain relief came from just two tokes. I am a lightweight! Hope that helps.
PS, I'm thinking that eating a high CBD strain is the way to go for multi-day pain relief, as the effects of eating it last longer.