@smcguire33
Business expenses are those expenses that are ordinary and necessary for the kind of work involved. Ordinary means usual or customary for that line of work. Necessary means necessary for that kind of work, although necessary does not mean essential or indispensable. The type of expense obviously varies depending on the kind of work being done. If you are starting an independent software coding business, you need a computer and an Internet connection and advertising and maybe a website. If you are starting a landscaping business you need tools and a dump truck and so on.
A start up expense is simply an expense that occurs before the business is active. The definition of an expense is the same, ordinary and necessary. With the caveat that assets, which is usually defined as durable items with an expected life of more than one year, must be placed in service as assets in the usual manner and are not treated as expenses, unless they fall into one of the safe harbors.
