I appreciate the post Adz.
I used to work with a guy that had a S Corp. In the summers, he was a pro fisherman. He told me that he "had to make money 3 out of every 5 years to continue." or the IRS would call it a hobby.
My brother was or is a consulting QC expert and Reliability Engineer. He never seems to truly retire. He used to file estimated quarterly taxes. He is the only person that I know who does it that way.
Anyone who is a freelancer SHOULD be filing quarterly taxes after the first year. If you don't, you can be hit with penalties and you have to pay it all at once which can be difficult. We use a lot of freelance labor in the animating business and I remind them to do this. With the young ones a lot of times we would have to pay them in advance at tax time just so they could pay their taxes. But most of them learn.
My "old" company is being bought. We were an S Corp and that is true about having to make money. BUT, the way S corps run, you also have to zero the company out every year, so you have to walk a very fine line. I won't get into all the ins and outs of that. The new company is a single owner LLC and has to file quarterly estimated taxes, but the taxes are based on more than just what
our company does. Honestly with this, I'm glad I'm "just" a bookkeeper!