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Most people looking for investment will purchase some sort of property and rest it out to help cover their costs. A lot of these will sell it before they have realized a good profit because they find having a tenant is more trouble than it is worth.

I propose to you that land investment be the way to go mainly because in many situations buying and empty block of land is a lot more affordable and because as time goes by the amount of land available decreases the value should increase making the lucky investor a whole lot of money to put in their retirement fund.