the feeling of “I’m about to have a seizure” (I have focal epilepsy without loss of consciousness) can come in waves for a period of 1-2h and when the seizure “explodes” it’s about 1min but that’s just the actual seizure.

Not long usually, but at night not sure I sleep through them, and few I didn't know someone told me, that was about 10 mins, my answer

I have both petit mal seizures and grand mal seizures. The petit mal seizures I have last around from 10 seconds to a minute. As for the grand mal seizures I have it usually lasts around 2 minutes to 5 minutes. When I have the grand mal seizures I fall into a deep sleep and I end up falling on the ground. Most of the time the doctors end up telling me at the emergency room that the grand mal seizure I had was from either a lack of sleep, stress, or dehydration.

I have very short seizures. They last between 20 ~ 60 seconds .
My blackout seizures, last from micro seconds- 2 seconds.

Depends on tje type and how stressed i am. Average is 15 seconds- 4 minutes.