You can, but if you don't make the exact same $$ amount as the other three payments (or if the other payments are not equal) then you may be stuck filling out the messy Form 2210AI (annualized income) to avoid the underpayment penalties ...even if you still overpaid. Work thru that form once, and you will attempt to avoid it in all future years
My preference is to always pay 4 equal installments unless there is some "massive" unexpected income event during the year.
Certainly, some self-employed folks are used to having widely variable income by quarter, and they do make variable quarterly payments, but they are more used to keeping good records on their income and deductions by quarter. Whereas, most people don't do that and gathering all the detailed information together after-the-fact can be a massive chore.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
