That just means the variable isn't named correctly, not that it needs a comment. Just name it 'time_seconds" or whatever and save yourself the extraneous typing.

I tend to be a minimalist when writing comments. If I have to write out a comment to describe what I'm doing (like "advance 1 simulated second"), then I have failed at writing clear code. Sometimes I will write a comment to explain why I am doing something, if it's not clear (like "manually advance time to work around frobbing bug in foobar").

Comments add to your maintenance burden. Writing clearer code can often reduce that burden.