We follow JEP ( “Just Enough Processes”) which is essentially defined taking into mind the following factors:

The tasks to be completed

Time frame for completion
We make sure our team overlaps 2-3 hours of every customer time zone so that there is effective co-ordination and any questions our developers have during our day can be resolved by the time they go home through 2-3 hour overlap with the customer team. We strongly believe for an early stage company during their prototype and ver 1.0 following standard processes may not make much impact since every companies priorities on their time to market and other constraints differ drastically.
These are leveraged by our customers and also help us in maintaining uniformity in processes and practices across customers.