Buy-to_let VOIDs and / or Losses

According to the ARLA newsletter for the last quarter of 2013, average tenancy lengths reported by landlords were 19.4 months, down slightly from 19.6 months in the previous quarter. The average void period was up from 2.9 weeks to 3 weeks.

This would indicate a loss of rent through voids of around 3.5%, which is very similar to the 3.6% figure quoted by IPD.
ARLA do not publish figures for losses from bad debts, but IPD quote 1.6%.

So a reasonable estimate of average rent losses to expect from voids and bad debts would be between 5% and 6% of gross rent. Bad debts tend to be lower for professional tenants, than those more vulnerable to unemployment or dependent on housing benefit.