Spreadsheets are great tools. Spreadsheet programs have been around for over 25 years and many contractors have built some pretty respectable spreadsheets over the years for their estimating. Spreadsheets essentially allow you to setup your own formulas for adding, subtracting, multiplying and dividing so all calculations and extensions involved in estimating can be done quickly.  

You can also build different spreadsheets for different types of work so you don't forget costs in your estimate. There are many advantages of spreadsheets that detain many contractors from investing in database driven estimating programs.

Database Driven Estimating Systems
Database driven estimating systems have the same features as spreadsheets but are able to incorporate and integrate multiple processes and procedures into a single entry solution. Many contractors are deserting spreadsheets and moving toward database driven estimating systems because they can incorporate more of their internal processes and procedures like lead tracking, proposal writing, project management, scheduling, and job cost accounting into their estimating system. This way they can streamline their business and bring more profit to the bottom line.

For example, Contractors Software Group's (CSG) Plus Series product line integrates (or transfers) its SalesBuilder Plus information, a lead tracking system, with its Takeoff Plus (an estimating system) so users don't have to re-enter the same information more than once.

Aside from offering a full blow estimating system, CSG has also incorporated the ability to add specifications to an item, assembly or bid sheet template.  So while estimating, you're actually creating the customer proposal/specification at the same time. These detailed or summary proposals sort the work to be performed by category of work and or by location.