Using controls on worksheets
Excel is a very flexible instrument to perform analyses and what-if scenario’s. You use formulas in cells with one or more input cells to calculate the various situations. To ease working with different values and/or choices, you can put the controls from either the Control toolbox or the Forms toolbar to good use. Proper use of these controls make your models easier to use.
The controls also enable you to ease data entry and at the same time improve data quality by minimizing the risk of wrong entries. For "day-to-day" use, I recommend the Forms controls. If there are specific options you need which are not offered by the form controls then you can also implement the Control toolbox (ActiveX) controls.