Is it reasonable to ask update on recommendations letter twice? It is important to know that I have requested about 7/8 letters per professors ( 3 total ). I have told them that I was conscious that it was a lot of letters to write so I was content with a general letter for most of the schools I wanted to get in and maybe one letter that was a bit more personalized for the school they felt I would have the highest chances of admission.

The nearest deadline is 10 days away. I have asked about this in late January and I haven't gotten anything yet.

I asked for an update in early March and the profs were either working on it or were being bottlenecked by the administration. But since then I got nothing.

The deadlines are approaching quickly and I hope you understand how stressed I feel about this. Would it be too petty to ask for a second update?

I need at least 3 letters, and I have only asked to 4 professors, one of which didn't answer so I think he doesn't want to write me one (for a reason I ignore). I may have made a mistake and should've asked more professors, that's on me. The point is I don't want to upset because if at least one of them decides that I am too annoying I can already cross half of the schools I wanted off the list.
You can stop worrying.

It is not unusual for professors to wait until the last minute to write letters.  Although busy, they are experienced at meeting deadlines and will get it done.  It only really takes an hour or two to write a recommendation letter, and submitting it to 7-8 places is no big deal at all.  What you've asked of them is completely reasonable.

It is certainly fine to contact them, though I don't think I would phrase it as "asking for an update".  I would write an email like:


  Dear Professor X,
  
  Thanks again for agreeing to write me a recommendation letter.  I just wanted to send a friendly reminder that the first deadline is April 1 (for University Y).  The remaining schools and dates are in the list I sent you previously.  
  
  Please let me know if you find that there is anything else you need.  
  
  Sincerely,
  
  truvaking


Also, if you have recently made any significant accomplishments that you think they might want to mention in the letter, you can communicate this in your email as well.

I really don't think you will upset anyone by doing this.  It would be incredibly petty and unprofessional for a professor to go back on a promise to write a recommendation letter, solely because the student sent some reminder emails.  Likewise, I think it is still fine to re-contact the fourth professor if you think their letter would be helpful.  They may have simply overlooked your original request (professors get a lot of email).