I sell scheduling software SaaS for a niche in the medical world. I label my emails “question”, “problem”, “suggestions”, or “administrative” (anything related to paying, changing account names, etc…).
Some emails are double-labeled, so that’s why sum > 100%.
I don’t differentiate between pre-sales and post-sales questions (probably should).
I also label phone calls and it’s a similar ratio.
Some of the “problems” are actually users thinking there is a problem, even though they are actually mis-using the software or expecting magical things to happen. I use the tone of the email for the label, not the actual existence of a bug.
Note that I sell to institutions and accept POs, and my users/contacts are not very computer-savvy which is why the admin label is fairly high.
To lessen the burden I have found that making the software gobsmackingly self-explanatory really helps with the “questions”. I could cut it down further with top-notch high-level overview articles of capabilities and best-practices.
Also I fix bugs ASAP when I identify them. This cuts down on the “problem” label, churn, and abandoned trials.