Frankly speaking, I don't like to renovate old things. I would prefer to order a new one, then spend a lot of time sanding old paint, re-coating, and waiting until the door dries and the acrid smell of paint at home disappears. Time and health are in priority for me. To tell the truth, nowadays the prices on the finished doors are really good. For example, we ordered some new doors for our first floor last year from https://doordesignlab.com and the total amount was really very affordable and pleasant. Honestly, I thought that it will cost more. More than all, when you paint by yourself, you don't have special equipment for this: a compressor and special paint gun most likely you will paint with a brush, so the result will not look so perfect. You even can spoil the door altogether.