When not to buy a pre made software package

Building customized software can get expensive, which may make an off the shelf system seem more attractive. But it’s important to realize that pre made software cannot always meet every business need. Generic software can also straightjacket a company's operations. For example, software establishes operational policy simply by the way it functions. If the software cannot meet certain customer needs, the company will be forced to “go off policy,” in other words work around the software, to address those needs. So, it’s important for the software, that a business uses, to match established policy and procedures. Software should enhance and not confuse operations. This isn’t always possible with canned software. Off the shelf software makes it difficult to alter functionality to match specialized requirements. So, the first question to ask is does your company have requirements that would make it difficult to find an off the shelf match? If so, building your own may be a viable alternative.
Compatibility is another problem with off the shelf applications. Different applications designed to perform different but related tasks must be able to easily communicate with each other. If they can’t then efficiency may be hindered.
You should consider building rather than buying pre-made software when your company is using vital legacy software that cannot or will not be replaced for some time, or if your business operations have specialized requirements that are not directly addressed by off the shelf applications.
Custom built software can be worth the price if it will help your business operate more profitably in the long run, providing the budget, technical expertise and time to build are available. Ultimately, it comes down to competitiveness. Will custom built software give your business a competitive edge? If the answer is yes, then building your own is probably a good idea.