How often do you reevaluate your customer segmentation criteria?
I recommend constantly evaluating the performance by segment (at least quarterly) and doing a segmentation review once a year with annual planning!
In my experience it makes sense to reevaluate your customer segmentation in conjunction with your annual or half year planning in the context of your broader business goals (i.e is your business trying to move upmarket? downmarket? are there new personas or industries you're trying to target)
There can also be major company milestones like new product launches or M&A that warrant you to evaluate your customer segmentation.
Additionally, if you're looking at segments for your campaigns and pipe-gen efforts and you're running targeted campaigns against certain segments and cohorts, you'll want to evaluate the performance of your marketing campaigns at the segment level to determine effectiveness and any changes you want to make.
It depends on a few factors.
How is segmentation being used ? - for campaigns, to generate pipe, for sales motions ?
At what stage of the sales cycle is segmentation proving to be most effective ? early qualification or pipe-gen vs mid-stage ?
In order for broad pipe-gen efforts, cohorts are often more helpful than pure segments based on basics such as demographics, age, buying power, titles, etc. They are a start.
Revaluation on a quarterly basis is helpful, but must be aligned with the goals for re-evaluation. Why re-evaluate ? Is the current segmentation not yielding results or is too broad ? how long has it been in execution ?