Monopoly: Property Improvements
Improving property (buying houses and hotels), is one of the most important things you will do in advancing your position in the game. Property improvements drastically increase rents. A player without improved properties is pretty much doomed to bankruptcy in the face of other players with improved properties.
The rules stipulate that improvements can only be made on properties where a monopoly is owned (all of a color group). Then the properties must be improved in as equal allotments as possible. This means that you can have no more than one more house on any one property than the other lots in the monopoly. You must have four houses in order to buy a hotel. However, the purchases may all be made in one turn. Improvements of property can not go beyond the number of houses and hotels provided with the game (32 houses and 12 hotels). The effect of this can be to limit some players' ability to improve, even when the financial resources are available. However, this point is seldom reached before the outcome of the game becomes fairly obvious.
Property improvements should generally take place using the same rule as for property, "buy, build, build". Certainly it is prudent to make provisions for landing on the property of others. However, if you keep putting money back to pay the highest rent you are like to encounter, then it becomes almost inevitable that you will end up paying that rent. However, if you put aside only enough to pay moderate, normal expenses, then you are likely to be collecting enough big rents to pay for the big expenses when they come. Also, there is a chance that your improved properties may be the direct reason the built up opponent's property you so feared had to be mortgaged.
Generally, every Monopoly possible should be built up. But which properties are best to be built up? Sometimes this is a question of where your opponents happen to be on the board. If there are a cluster of them between 5 and ten spaces from your property, by all means, build up these properties. However, all things being equal, it is best to build where you can get the biggest bang for your buck. As a rule of thumb you can figure that for any side of the board the more advanced on the board a property the higher the rents. For example, the light blue have higher rents than the dark purple, the orange better than the purple, the yellow better than the red. But per dollar invested, the light blue with hotels is the best bargain. Consider that a hotel on Connecticut costs a cumulative $250 and garners $600 per hit. This is a whopping 240% return every time it is hit. The closest to Connecticut are Boardwalk and New York Avenue, both getting 200%. The worst is Mediterranean, which gets 100% (which is still pretty respectable, all things considered).
Now consider the fact that the biggest increase on any rents is between the second and third houses. Generally, the improvement more than doubles the rent and is sometimes as much as three times. The next increment is not as great (but still good). This means that it can be best to improve all of your properties to the level of 3 houses on each before moving on to hotels.
All improvements are good. Some are just better than others. Simply remember the rule, "Improve or lose!" (Also known as "build, build, build".)