Very broadly speaking, investors expect 3-4x of invested capital within three years and more than that for any longer period as pretty much the minimum for a given investment.
Early-stage investors are prepared for several of their investments to fail so their return criteria may are likely to be considerably higher. This also means that the required return on the entire fund is going to be lower than the required return from any one investment.
Note again that these are very broad-brush statements that do not apply to all investors.
Exit period depends on the type of investor and the stage of your company. If you are a 10-year- old company raising money from late-stage investors, don’t expect that they are looking to invest for a further 10 years.
This is a cross-post of my latest column answering entrepreneurs' questions for Yourstory.com.