There are several options when considering how much work to do before selling. One option is to do little and sell the property in it's "as is" condition. Another is to invest time, effort and money into fixing the property up before you sell. A third option is to find a middle ground between the first two.

In general buyers pay more for homes that are in move-in condition; a home in great condition will usually attract more buyers than one that needs a lot of work.
There is a market for fixer-upper properties, although it is more limited. Fixer buyers will pay more for fixers that have a big upside potential but fixer listings sell at a discount when compared to listings that are in move-in condition.

Besides a higher price another benefit to fixing up your home for sale is that you have control over the improvements. You can shop around for the best price and this alone can save you as much as 15 to 30 percent.

Often time will decide how much work you will be willing to do before putting your home on the market. It's best to plan ahead because, depending on what kind of work needs to be done, it can take months to get a house ready to sell.
Consult with your real estate agent before embarking on major work; plan to walk through your home with your agent and take advantage of their expertise to make a list of all the items that should be done before you sell. Your agent can help you prioritize since some projects may be too costly and some may not be able to be completed within your time frame. You can then get estimates for the work that needs to be done.

Whether you fix it up all the way, sell it "as is" or something in between remember that putting your property into a clean and uncluttered state can only make the sale easier.