Open APIs

Hi All,

I'm looking for information on how the UsageSpecification resource is used in practice with TMF635 to help choose between a number of solution options. 

For those who've implemented TMF635:

• How often are GET /UsageSpecification calls made in production? 
  • Is this something used interactively in flows where POST/GET /Usage calls are being made?
  • Do client applications retrieve UsageSpecification periodically or on startup?
  • Is it even used in production API flows?

Any feedback will be hugely appreciated!

Thanks,

Phil