We always go hard. But there's benefit in going lighter. Especially for newbies. It teaches them to ``box`` and not ``fight``. There`s a big difference. I think the occasional light session helps fighters to think more strategically. Then when sparring hard, they are more likely to apply them, rather than losing composure and just going hard.
Gotta mix it up Hard for conditioning and develop solid timing and give good preparation for fight night Light to try and practice new techniques and try different strategies.
There's a natural process that happens, starts out as light sparring turning into hard sparring after a few rounds.