Long-term voids can consume spare cash and in the worst cases can even cause a landlord's business to fail. However there are a few things you can do to help soften the impact and avoid them occurring.
 
1. For first time & small landlords voids are a serious business
Landlords with a small number of properties are more reliant on rental income to cover mortgage payments and repairs. So if they stop receiving rent they may find themselves in negative cash-flow.  Repair issues are often unexpected, so you should make sure you have savings to cover the double whammy of repairs and a void at the same time. Once you have 5 or 6 properties you should generally have enough cash-flow across your portfolio to cover a void in one of your properties.

2. Get the right business model
Aim to acquire properties that are easy to rent, so research carefully before you buy.  Know your area and the local lettings market and tailor your properties to suit demand. Build in some flexibility as the market might change. For example, landlords who bought one bed flats with a view to letting to people on benefits a few years ago will have been hit hard in 2013 by the fact that benefit claimants now have to be over 35 to get the one bed local housing allowance rate. Many of these tenants have had to move into shared houses. Stay aware of legal and regulatory regimes especially regarding licensing and article 4 planning directions. Golden rules for locations
are: close to public transport, amenities, good schools and sources of employment or education.