Congratulations on quitting smoking
. Altered taste
in mouth and poor concentration are due to tobacco withdrawal. The reason you could not find any mention of exact duration of withdrawal symptoms
is that there actually is no exact duration and this varies from person to person. In your case, going by your history of smoking for 39 years, I would say that you will continue to experience at least mild symptoms for around 4-6 months. But the good news is that health benefits of quitting smoking start within days of quitting and you reduce your risk of developing heart diasease and cancer. Moreover, the discomfort also gets better with time. The first month may be hell for you, but it surely will be better the next month. Please also avoid exposure to second-hand smoke if you want to get well soon. Have faith in yourself. The worst is over and it just gets better with time.
Best wishes for a smoke-free life.