I prefer to think of this as "working smarter, not harder", but maybe I'm just lazy! I wanted a plant that didn't need a lot of care and I wanted to print a planter that didn't need any sanding or sealing to use.
So naturally I decided to buy the "lazy person plant" (a succulent) and designed this planter where the original plastic pot just fit right into it! Of course, the plant may not grow as big as it could if I re-potted it, but that's fine by me. The standard size plastic pot that fits into it is approx. 3.5" top diameter, 2.5" bottom diameter and 3.25" tall.
Also, if you're not lazy, I suppose you can still re-pot into the planter as there's a drainage hole in it.
If you want a drainage tray, here it is: https://www.thingiverse.com/thing:3751456
The bottom surface on the inside is slightly irregular because of the modeling tools I used to design it, but it prints just fine and no one will see that after a plant is in it.