Even 6" stretch is no big deal once the plant gets bigger so I use supports if needed until the stem is strong enough to stay upright on its own. You want some space at the base for better air flow to prevent moisture being trapped around the base possibly leading to stem rot.
Most of the time I don't get much stretch and once the stems aren't so easy to break I whip them around with my fingertips to toughen them up. They look beat up after but stand tall by the next day.
Under my old T-12 - 8-tube bank of lights with little stretch for a SoG grow a few years back in 2017. I beat the crap out of those girls all from seeds.