Is it fine to evoke the same spirit or different spirits more than once a day or should you do it only once? Would that be annoying to the demon if I evoke them more than once in a day?
You can do as many evocations in a day as you want to. However, if done right, evocations can be quite draining, physically and spiritually, so the quality of your second evocation might go down.
No, it will not annoy the demon if you evoke it more than once a day, as long as you let it know why you are doing so.
Yes, you can evoke different spirits on the same day. Many here have done so. I myself have evoked an Elemental King in the afternoon, and a Demon King in the evening.
I have read recently that if you don’t space out your big works like evocations etc and diversify the methods you use, you could potentially wear out your endocrine and/or immune system a bit over time and put yourself on bed rest for a week. (Muscle aches and fatigue, fevers, etc.)
I did evocation of Azazel and I went 2 weeks like “with amphetamine” and I slept maybe 2-4 hours per night for 2 weeks. Then my friends started to say you look kinda tired a bit. So much energy after ritual. But it’s true you can feel also drained and lack of energy after a ritual. Anyway grounding yourself back to earh energies is always good after any ritual. I have forgotten to do it sometimes and I noticed missing energy a lot. Remember to do evocations with respect.