Smallest practical grow size

I’d love to do have a plant or two. I think it would be fun/rewarding. I have a med card but I understand I will get much better quality than in our Florida dispos.

“Problem” is most of the harvests I see posted would last me a few years. What is the smallest practical size plant and how do I keep it small.

Indoors or outdoors is acceptable. I’d rather grow outside if I can. I have plenty of sun and rain. Biggest concern is too much humidity…mold.

Appreciate any and all recommendations.