Work one gets at least 4 years of life, it's not good for value beyond that due to write-offs etc, which is somewhat strange when you think about it. After that

Work one gets at least 4 years of life, it's not good for value beyond that due to write-offs etc, which is somewhat strange when you think about it. After that, they are sold to whoever wants them (we wipe them, clean them and unlock them). Most people get close to 8 years before they actually want a new one when their work doesn't change much -- if your requirements don't change and your tool fits, no reason to change.