What Processes and When?

Why Establish any processes?

Process definition and maintenance cost time and energy so you need to make sure you get more value from a process than it costs to establish, maintain and work.
When you are considering whether or not to establishing processes you need to ask the following questions:
How frequently do we do the same kind of thing over and over again? Is what we are doing critical to the quality of our products or services? Does what we are doing impose any risk to our people, our customers or our company? Does it relate to how we evaluate our people and their performance? Does it impact the bottom line or how we are perceived as a company?

When does it make sense?

If you answered "Yes" to some of the above questions then it is probably worth exploring the establishment of some type of process to help ensure that what you are doing is done in the way you need it to be done. Establishing a process will help ensure that we have defined exactly what we are doing and why, that we are establishing a method to achieve consitent results and/or performance, that we are establishing the appropriate information that can be used in continuous improvement, performance evaluation and proper communication and signaling.
If you answered "No" to all of the above then it may not be worth exploring whether or not you need to establish some type of processes.