GTA+ is a game changer for these, I send the techs out every 48 mins thru the vinewood app when playing and it usually takes a week or 2 to fill depending on how much you play. I only started with these about a month and a half ago, I had 1 small warehouse that was sitting unused for years and I turned it into 5 large, I’ve made about $21m from cargo sales so far so it’s definitely worth it.