Buying “big” software like an ERP package, salesforce automation or CRM can be a harrowing process. Your offices are besieged by software and implementation providers, business stakeholders offer conflicting requirements, and you are rarely sure if the budgeted time, money, or both are adequate. Further complicating matters is the fact that you will likely have to live with the software for years, potentially struggling through a multiyear implementation process and then enhancing and maintaining a technology that may be with you for decades. With the long road ahead in mind, these tips can help ease the process:

1. Buy based on the business case

Big software vendors are experts at flashy pitch sessions, where neat features are spotlighted and amazing efficiencies are promised. While these are all well and good, most big software implementations fail due to adopting the software to meet one specific business requirement. Evaluate your software decision in light of the business case that triggers its purchase, and demand the vendor demonstrate how their software will support your other key business processes. Even the most compelling feature will be worthless if tens of thousands must be spent to adapt the software to your needs.

2. Factor in all the costs

Perhaps the most pressing pain of big software is its costs. The best way to get a handle on cost is investigating past large implementations at your company. Look at the amount of customization that was required versus what was expected, and use that to extrapolate implementation costs. Failing that, multiply your expected implementation costs by two, especially if they seem incredibly low or rely on some newfangled methodology the vendor is pitching that they claim will make implementation nearly painless. Usually these “best-practices” methodologies are not all they are cracked up to be, and the promised benefits evaporate almost as quickly as the vendor sales staff once the contract is signed.

3. Get “real” references

It is certainly expected that you will ask vendors for references, and most will provide you with glossy “case studies” riddled with compelling quotes, with a “company just like yours” detailing how the package went in “on time and under budget, and brought about world peace in our time.” These should be regarded as marketing copy rather than references, and you should insist on talking with current and past customers of the provider. Past customers that the vendor provides were likely successful implementations, but currently implementing customers represent more valuable feedback, since the jury is still out.

Don’t shy away from trolling the Web for “horror stories” about that particular package. Assuming you are in noncompeting industries, most companies would be more than happy to talk with you and detail their experiences with the software and provide some caveats. Even across industries, sales, logistics, and back-office functions are remarkably similar, and with a sample of three to five businesses you can quickly discern if there is one area of the software that presents a frequent problem.

While this is just a sample of the many facets of implementing a massive enterprise software package, it will serve as a high-level guideline as you embark on the long journey of “big software.” These types of implementations have made or broken many a company, so proceed with careful consideration, keep the business case in mind at all times, don’t fear bringing in impartial advocates, and stack the deck in your favor.