A. No. For people in the 10% to 15% income tax brackets, capital gain tax rate is 0%, so tax loss harvesting does not make sense for these people. In fact, at such income level, one should harvest gains, not losses.
However, if you are young and earning less than what you will be in the future, you could get up to $1,500 per year ($3,000 per couple) in losses and deduct that from your income, a tax loss harvesting that results in such amount makes sense.