Such a difficult question , and I asked my rheumy the same question. Her guidelines look at the question kind of related to flares and morning/evening stiffness. For example, if I experience 1-2 flares between doses or in morning and evening joint stiffness lasts more than an hour, we will start to look at other options. But I am often reminded that it can take up to 6 months (depending on the treatment) to even know if it is working at all. So that is also something to keep in mind.
I would also suggest speaking with your rheumy as your body might have different "signs" that a med is working or not. They should be able to give you a more specific answer.
I know it can be really frustrating and there is a lot to consider when it comes to switching meds. Unfortunately, what it seems to come down to is everyone's best "guess."
Hoping you have a few pain free days coming up! -Leanne, Community Moderator