Quick answer: Watch for players repeatedly asking about known problems, support tickets that are duplicates of known issues, players unaware you know about issues, and wanting to deflect routine support. A known-issues page deflects duplicate support.
A known-issues page is one of the highest-return support tools, deflecting a large share of duplicate support for little effort. Here are the signs your game needs one.
Players Repeatedly Asking About Problems You Already Know
A sign is players repeatedly asking about problems you already know, the same questions about known issues. If players keep asking about issues you're aware of, they have no way to see what's known, a known-issues page would let them self-serve, deflecting the repeated questions and reassuring them the issue is known.
Bugnet groups crashes by signature so you know which issues are recurring, and offers a public tracker as a known-issues page. Players repeatedly asking about problems you already know is a sign you need a known-issues page, it would let them see the issue is known (with its status and any workaround), deflecting the repeated questions and the support they create.
Support Tickets That Are Duplicates of Known Issues
A sign is support tickets that are duplicates of known issues, much of your support being players reporting or asking about problems you already know. If duplicate tickets about known issues are a big share of your support, a known-issues page would deflect them, since players could check the page instead of filing a ticket.
Bugnet's public tracker serves as a known-issues page to deflect duplicates. Support tickets that are duplicates of known issues are a sign you need a known-issues page, it deflects the duplicates (players see the issue is known and don't file a ticket), which reduces your support load by letting players self-serve on the known problems that make up much of your support.
Players Unaware That You're Aware of Issues
A sign is players unaware that you're aware of issues, filing reports or complaining about problems you already know and are working on, because they can't tell you know. If players don't know you're aware of issues, a known-issues page shows them, reassuring them (and deflecting the report), by making your awareness visible.
Bugnet's known-issues visibility shows players that issues are acknowledged. Players unaware that you're aware of issues is a sign you need a known-issues page, it makes your awareness visible (players see the issue is acknowledged and being worked on), which reassures them and deflects the reports/complaints that come from players not knowing you already know about a problem.
Watch for players repeatedly asking about known problems, support tickets that are duplicates of known issues, players unaware you know about issues, and wanting to deflect routine support. A known-issues page deflects duplicate support.