Hypocrisy is only a heuristic (and a pretty bad one), it doesn't impact the rightness or the wrongness of the advice given. Someone who smokes telling you that

Hypocrisy is only a heuristic (and a pretty bad one), it doesn't impact the rightness or the wrongness of the advice given. Someone who smokes telling you that smoking sucks and you shouldn't do it is a great example; do you dismiss them out of hand because they're a hypocrite? All claims should be evaluated on their own merits. The author's selling a book has nil impact on whether their thoughts about consumerism or minimalism are correct.