We designed our own methodology. We also install all modules of our apps initially and then have different license keys for each of those modules (similar to others who have responded here). In over ten years, we've only had one instance where this approach caused a problem with an installation -- and that turned out to be another app (not one of ours) trying to access the modules list externally.

Quite frankly, we didn't want to rely on someone else's way of doing things, which might change and break our apps or overly complicate their installation by our users. We also felt (and still feel) that the ability to "instantly activate" a new module is a *feature* to our apps, and as such we wanted a bit finer control than we would most likely receive with a third party solution.


>Did you design your own license key or do you purchase someone else's?
>
>Just curious. We rolled out own and it seems to work pretty good, but I'm just wondering if there are third party options that provide a more reliable solution.
>
>>We started, about two years ago, using a "license key" which does exactly what you're describing. It works well and wasn't too difficult to implement.
>>
>>>Just wondering if anyone (besides us) uses activation codes and what your thoughts on them are?
>>>
>>>Our purpose for using an activation code is that it allows us to distribute a full-function demo version of our application that will stop working in 30 days. If they decide to purchase it, we can provide an activation code that will convert the demo into an unlimited version.
>>>
>>>What is everyone else doing for commercial applications?