Even a fully leased community never stays full for long. Each month a slice of leases comes up for renewal, and the residents who don't renew move out, so occupancy is something you re-earn every month rather than win once. Each move-out feeds a pipeline: it becomes a make-ready, then an available home, then a new lease, and each stage clears only so many homes a month. When move-outs outrun your turn and leasing capacity, vacant homes pile up even when demand is healthy, and holding renewals is the cheapest fix, because a vacancy costs 2-3 months of rent and a make-ready costs 1-2 months. This model runs the full chain through a Monte Carlo lifecycle engine to build intuition about each lever: the standing vacancy, the months of supply, and net revenue against gross potential rent. Move the three levers below and every curve recomputes live.