Great, I was about to post the same message.One huge (huge) mistake people make is the exact one you said, which is "My commute is only 40 miles round trip, if the car has 200 miles max range I would only have to charge every X days". It doesnt work like that.
The TL ; DR version of that is, if the car has 0-100 250 miles range, you will not be driving it from 0-100, hardly ever. You will be charging to a max charge rate of 90% of 250, and "running it down to" a minimum charge rate of somewhere between 20-30% on average. So, you will be charging to approximately (when new) 225 miles of range, and driving down to approximately 75 ish miles of range, or approximately 150 miles. If miles rolled off at 1:1 (they dont) thats charging every 3-4 days, not every 5-6 days. Since miles dont roll off at 1:1, it will be charging every 3 days or, 2-3 days.
Like I said, I could not imagine leaving my car at the grocery store while It charged and I went home, on a every couple of day basis, but if that enthuses you, then go for it.