Many nonprofits have a portfolio of grant proposals that they simply update by changing the submission date and possibly the funder's name. After all, it's the same program, seeking to accomplish the same goals, so why not save time by using cut-and-paste proposals?
I see this often when dealing with clients who routinely approach the same funding sources year after year. The problem with this is that while the framework of the program may not change, other things do. Sometimes the actual RFP may be phrased differently, or the foundation's focus may have changed slightly. Other times, the statistics from the nonprofit side differ from the previous year.
It's rather embarrassing to receive a denial letter that notes that the foundation is no longer repeatedly funding the same organizations, or that the maximum award is now $5000, and you asked for the same $10,000 they have always funded for you.
Even worse is providing out-of-date information. If you are still using last year's board list, but three members of the board have left and been replaced with new people, it looks like you don't know what's going on in your own organization. Community foundations are often well aware of who sits on whose boards, and providing old information is a red flag that someone didn't take the RFP seriously.
When using statistics, keep them current. If the population demographics you serve have changed, be sure that your proposal reflects the changes. If the grant requires specific information regarding demographics, using statistics from three years ago may not support your request, or the results you cite may not match the new demographics.
Make sure that your proposal matches information on your website. Many RFP's ask for your website address, and some review committees routinely check the website for discrepancies.
Aside from these obvious problems, using the same tired copy over and over simply robs your proposal of impact. Try to maintain a fresh and dynamic view of your programs, and let your enthusiasm show in the proposal.