A business with its focus on growth will be expanding its workforce. So if your software is licenced to you on a per user basis, you will see an exponential increase in cost alongside your employment activity.
For some this won't be an issue because the users will be minimal but if your sales team is the driver of turnover or you house a growing commmunity of phone operators or you need the office to manage more of the customer service enquiries, your user numbers will increase.
If we consider the following options of a standard off the shelf CRM, you'll begin to see where you sit as a business:
1. A free version of a product that usually allows one user and has a range of features that you can compare against the paid for options. They may offer integration with accounting packages.
2. A lite version of a product that will have a monthly fee, a user limit and a range of features (they may charge per user or in groups). They may offer integration with accounting packages and other software such as Outlook.
3. A fully featured, paid for version which is based on a per user, per month fee and will integrate with some software and have a full support offering.
A licence is just that - and it has an implication of time attached to it. If you are looking at the longer-term aspirations of the company, work out the commercials of a licence-based model over a 5, 10 and 20 year time frame against an investment into the bespoke, ownership model. It's not a method that's suitable for every enterprise but it is certainly a costing exercise to carry out before you head down the licencing channel.