Hi! I can't speak for everyone but I have constant symptoms, mainly fatigue, brain fog, heaviness in my right side. I myself consider a flare up is when they are loads worse for more than a day or two, and I find this is usually brought on by stress or doing too much. This is from the nationalmssociety.org: An exacerbation of MS (also known as a relapse, attack or flare-up) is the occurence new symptoms or the worsening of old symptoms. It can be very mild, or severe enough to interfere with a person’s ability to function. It goes on to say: To be a true exacerbation, the attack must last at least 24 hours and be separated from the previous attack by at least 30 days. It must also occur in the absence of infection, or other cause. Most exacerbations last from a few days to several weeks or even months. My understanding is that this doesn't necessarily mean there is new activity (lesions) occurring, and this is the way RRMS happens... Relapse, remit. It's a minefield and everyone is different in their experience and approach to dealing with things, and it can definitely be confusing! As I say, this is just my interpretation and it could be technically incorrect but I hope it helps... Happy to chat if you'd like to ❤️