I’ll just add that the optimal ‘age’ for planting out tomatoes is 8 weeks old, from germination.
They’ve done numerous studies planting at 8 weeks, 10 weeks, 12 weeks and the 8 week old tomato plants catch up quickly to the others grown on in pots for a few more weeks.
Another reason I like my plants larger than fresh out of the 4-pack when they go in is that I can plant them deeper. All those hairs on the stem will become roots, so that benefits the plant, greatly. Also, planting them deeper gives them more protection from wind damage as they have a deeper ‘base’ than a more shallowly planted tomato.
I agree, and would add that the hairier, heavier stems are more resistant to cutworms and snails.