I bought my first vine in a gallon pot. It was very twigy (my last photo). Took two years in small pot to bear small fruit. Leaves drop in winter and skinny vines dry up so I cut them back.
Second big purple flower vine was a bit larger, still twiggy and planted in ground. It grew fruit the first year but very tiny ones. This vine keeps about 80% of its leaves and vines. After 3 years the vines and flowers cover an arch trellis. Many flowers and lots of larger fruits this year.
The big 5 gallon pot, tall 5 ft tall (staked) white flower vine I bought last spring and planted in the ground now looks scrawny, possibly because it doesn't get as much sun. But the leaves are very large and shiny/waxy which stay year round.