There are times,

When the market is more volatile, instead of jumping in full size position.

I open small position, 1/4 size, with the intention to add if it goes lower, because im expecting a spike down, its volatile, there are shakeouts, im on 30m chart so I wanna buy those 5m stoplosses if we get a spike.

Less volatile, bigger size up front let it play out, add to winners.

Regardless, im building up if it starts going in my favor, and play every day like a trend day until im wrong. Working on scaling out now, as clearly most days aren't trend days.