To estimate a potential death date for these devices, we scoured each manufacturer’s website, and then put two key questions to the companies: First, how many empty-to-full recharges — or “cycles” — can the product’s battery take until its capacity drops to 80 percent? (After that point, batteries usually degrade quickly.) Second, what options does an owner have to repair or replace the battery in their device once it is no longer under warranty?For example, Bose said popular QC noise-canceling headphones last 20 hours per charge and can take 500 full recharges. So for someone who used the headphones 5 days per week, we estimated its headphones could start to die in 5 years — without any official service option to replace the battery.Several manufacturers refused to share battery cycle counts. We also took into account our own experience with products, and published reports by other reviewers and users.