Glossary

Average Length of Stay (ALOS)

Also known as: Average Tenancy Length, ALOS

The average duration, typically expressed in months, that residents remain in occupancy before moving out, calculated across a trailing period as a core retention and turnover-cost planning metric distinct from the point-in-time tenant retention rate.

ALOS complements rather than substitutes for tenant retention rate: retention rate measures the percentage of a given expiration cohort that renews, while ALOS measures full realized tenure length across all residents, including those who renew multiple times, making ALOS the more direct input into modeling turnover frequency and its associated cost — turn cost per unit, vacant unit days, and leasing and marketing cost — on an annualized, per-unit basis. A property can show a healthy retention rate at each individual renewal decision point while still carrying a short ALOS if residents tend to leave after just one or two renewal cycles, so sophisticated asset management tracks the full tenure distribution and its trend over time rather than relying on retention rate alone to project long-run turnover cost. ALOS also varies structurally by unit type and resident demographic — studios and micro-units typically show shorter ALOS than family-sized units — so portfolio-level ALOS should be reviewed alongside unit mix to avoid misattributing a mix effect to a genuine change in resident behavior.