You should, at first. Checking a few questions by hand is the right way to find out whether you have a problem, and it costs nothing. If you are starting visibility research, use those checks to identify buyer questions worth following.
It stops working for three specific reasons, and until you hit them a tool is unnecessary.
1. One answer is not a measurement
Assistants return different answers to the same question at different times. Ask once and you have an anecdote.
To know whether you are absent for a question you need several runs across weeks, and to compare that against competitors you need the same treatment for each. That is the point where manual checking becomes a data-collection job rather than a curiosity.
2. Repeated checks become impractical
Twenty questions, three assistants, twice a week is 120 checks a week. Recording each answer, noting which brands appeared and which sources were cited, and keeping it comparable over time is several hours of work a week nobody will do by March.
The realistic failure is not that manual checking is impossible. It is that it happens for three weeks, then stops, and the series has a hole in it that makes the earlier work worth less.
3. Your account affects the answers
Answers can reflect your previous conversations and your account's context. You are also the least neutral reader of a question about your own market. It is difficult to ask a question about your category without phrasing it the way you would rather it were asked.
Fixed, recorded prompt wording removes both problems, and it is the wording that makes a series comparable at all.
What recurring collection adds
A stored history you can compare, so a movement is visible rather than remembered. The cited sources for each answer collected in one place, which is the most actionable output. Competitor comparison under identical conditions. And the ability to notice a change you were not looking for.
When manual checking remains correct
If you have three questions and want to know today what the answers say, ask them. If you found a wrong description of your product, open the source page and get it corrected; no tool is needed for that either.
Buy recurring collection when the question changes from what does it say to whether it is changing, and when the answer has to be defensible to somebody else.
When the questions need recurring review, assess whether scheduled collection will support that work. Keep manual reading in the process so you understand the recorded answers.
See why repeated answers vary, choosing what to track, or whether tracking is useful.