This question comes up in almost every brokerage interview, and the honest answer is almost always "it depends" — on the brokerage, the market, and what "leads" actually means in that office.
Model one: the brokerage generates and assigns leads
Common at larger franchise brokerages that invest in advertising. Leads are typically shared among agents on a rotation, and the brokerage usually takes a larger referral fee off any deal that closes from one of them.
Model two: leads are available but cost extra
Some brokerages provide access to a lead platform or paid ad program, but the cost comes out of your pocket, not the brokerage's marketing budget. Ask exactly what this costs monthly before assuming it's included.
Model three: you're expected to generate your own
Common at 100%-commission and boutique brokerages. In exchange for a better split, you're responsible for your own marketing and sphere-of-influence outreach from day one.
Neither model is automatically better
A strong split with no leads works well if you already have a network to draw on. Brokerage-provided leads work well if you're starting from zero — but usually come with a steeper split in exchange. Pick based on what you're actually walking in with.