Keeping to the point and only writing into the spec sheet what you require will open the project up to more vendors and keep the cost down. Adding features because they sound like a good idea may limit the field of vendors and therefore cost a lot. If you only want to consider something, make it obvious in the spec sheet by making it optional. When reviewing the bids for your specifications, keep in mind that the lowest priced system may end up costing you more than a more expensive system if it lacks expandability or necessary features. Review future expansion for increased readers, personnel count and added future sites.
Expansion is one of the most forgotten and also the most important part of a specification.
Plan for expansion by examining the limitations of the quoted systems and determine what it might cost to expand beyond your present requirements. If this type of planning is done when the spec sheet is being written, it will save you money and aggravation in the end. You can expect a lot of features. The question is, which ones do you need. Keep in mind that you should only ask for what you need to keep vendor options open and the price down.