Scouting with protoss

Hello Im a newish player to sc2. I know scouting is super important and what to looks for. I send my worker to scout the enemy after he starts the gateway on 13, I then see how much gas they took so I kinda have an idea what I'm up against. If the probe lives, is not chased away, and the map doesnt have a safe expansion, I leave him to block the expansion. My issue is the second scouting, Idk when or how I can get another worker in the base with the enemy now having troups. Is there another way to do this with out changing my builds to account for observers, oricles, or pheonixs?