The golden rule, as I recall, is "new, or worsening of existing symptoms, which last for more than 24 - 48 hours" is an indicator of an "attack".

For me, most symptoms will come and go (by removing the trigger) if they are related to heat, stress, fatigue, etc. However, when I have an infection (often a UTI) this can lead to longer term flare-ups, which may or may not develop into a full blown attack.

Generally the first thing I do is to keep track of my body temp (I am vigilant about keeping it in check!), and get tested for a UTI if I have new or worsening symptoms beyond 48 hrs. If those two are ruled out, then it pretty much indicates an attack is underway for me.

That's my personal experience.

Cherie