Under the rules of the simulation, new R&D projects can only begin on January 1, the day that you make decisions for this year. If you started a project last year, and the project is not yet finished, the spreadsheet does not permit any further changes for that product this year.

Tip: Plan your projects to finish in the current year, or if that is not possible, towards the end of the following year. Often you are better off doing a big project in several small steps, each ending in December, rather than one big one. This cuts the product's age in half several times instead of once. There are exceptions to this general rule, of course, which occur when the automation level on your product is high or in the Low End segment where older products have an advantage over younger ones.