BobS
Bjensen, the difficult thing about predicting future rents is that a multitude of factors will influence them. That is why it is unwise to predict rents based on one of those factors you may believe in.
On the demand side demographic factors such as # of people, their ages, family formation, their incomes, etc. can increase or decrease demand. The supply side is easier to predict because the for-rent housing stock is largely a given. Over time it changes at the margin due to new building, demolitions, condo conversions (or the reverse, back into the rental stock), vacancies due to foreclosures, etc.
If you can predict what each of these demand factors and supply factors will do in the future, then you will know exactly where rents will go. Everybody can have an opinion.
Final note: because many of these factors work at cross-currents, they cancel each other out. Thus rental changes over time tend to be slow and gradual, barring some huge event like a massive recession or local industry leaving (or coming in).
