When to follow up for recommendation letter I asked two potential referees, 1 month before application deadline, to write me a letter and both gladly accepted, and one asked me to write a draft (which I learned was a common practice). 

It has been 10 days and I have never heard from them after I responded thanking them for accepting my request (and supplying the draft to the one who asked). 

What is the best time to follow up with them without appearing pushy?

Also, one of my referees had an academic email address, which means the application system sent him an automatic electronic reference form by email, and I have no idea whether it was completed or not. Should I still follow up with him?
I'd wait until about 5-7 days before the due date, and then send a polite email reminding them that the letters are due, and offering to have the links to the forms resent if they need it.

There is a balance between being "pushy", and sending them a reminder too late for them to avoid feeling time pressure if they haven't written it.  I try to stay on top of things, but if I forget, I would prefer to receive notification more than a day or two before the due date.

Of course, if there's a situation such as "rolling admissions", where an on-time submission can still be a bad thing, I'd ping them earlier --- but a situation such as that should never come up, as you would have let them know that an early letter was really necessary at the time you made the original requests.

It might be a good habit, when sending them the "thank you for agreeing to write me a letter" message, to say something like "unless you ask me not too, I'll send out a reminder about a week before the due date".