I would like to be able to customize client billing dates. I tend to bill according to when a contract is signed for services and this of course rarely falls on the same day for each client.
On the other hand, the date I start a project (and thus billed for hosting/fees by webflow) may not be the same date I complete the project in the future (at that point I begin charging the client for these fees). Furthermore, dates may need to be changed in the future if services change or at client request.
A great asset to the fluid control of client billing would allow me to set and reset billing dates at any time and this be unique per client. This of course can come with stipulations (backdated/prorated payments, and/or limits per cycle/year).