It's Vegetas time: The Prince V. Cui, Zarbon, Recoome and Frieza - Dragon Ball Sparking Zero

[@dustingleason3573]

Vegeta can sense ki after his encounter with the earthlings actually. He just didn’t realize how much frieza was holding back

[@JustoT94]

I meant to come back to this comment and you're right. I think he sensed Gohan and krillin at one point and even sensed Goku getting stronger. But he just wasn't proficient with it at that time? Maybe due to using the scouters for a long time