A personal viewing log can help you remember what actually happened without pretending to be a formal benchmark. Keep it short enough that you will use it: task, date, relevant setup and result. The log is for your own decisions and clearer support conversations.
Avoid turning it into a store of passwords or private source addresses. Useful observations rarely require those secrets in the same document.

Choose observations that answer a question
Start with the decision you are trying to make. If you want to know whether a needed interface control is practical, record that task. If you are checking an account handover, record the stage reached. A log full of unrelated details can be harder to interpret than a few well-chosen entries.
Use ordinary result descriptions such as opened, not located or awaiting clarification. Do not mark a cause unless you have evidence for it. A factual symptom remains useful even when its explanation is unresolved.
Keep enough context to compare entries
Note the app identity and edition where relevant, plus the programme or administrative record involved. Record the observation date honestly. Do not use a later file-edit date as though it were the date of the session.
A hypothetical entry might read: selected the intended title in the television edition; the listed caption option was not present; account information omitted from the note. That identifies a useful question without claiming the entire library lacks captions or exposing credentials.
Use the same vocabulary without forcing the same result
Consistent fields make entries easier to compare, but do not require every session to become a pass or fail. Some tasks may be untested, not applicable or unresolved. Preserve those states rather than treating silence as success.
If an issue changes after a support action, add a new entry and refer to the earlier one. Do not overwrite the original observation. The sequence can help show what changed while avoiding a claim that the later result proves a universal fix.
Useful answers
Does a personal log count as a formal benchmark?
Not automatically. Describe its actual method, scope and limits; it may be useful for your decisions without representing a controlled measurement.
Should I overwrite a failed entry after something works?
Keep the original and add the later observation. The sequence explains the change more clearly than a rewritten history.