Battery replacement at $200/pair sounds like a great price, compared to the info in the following resources/threads on this site:
Your nifty charging case also has a rechargeable battery that may need replacement sooner or later. Or maybe it’ll be cheaper to buy a new one at that point, if the currently available charger works with your aids.
You want to compare rechargeable aid maintenance to the cost of disposable batteries? My standard for pricing is the shop here on Hearing Tracker:
It’s a reliable source for batteries, because they’re drop-shipped from one of the big audiology supply companies. I’m not citing the much-cheaper Costco because not everyone belongs to Costco. And I’m not citing Amazon because (while I love Amazon for many things) it’s hard to judge the reliability of the seller who sent the batteries to Amazon’s warehouse.
In the shop, Duracell size 13’s cost $21.99/80 = 27.5 cents each. A week’s use seems to be a common figure for size 13’s. So a year’s worth is 52x2 = 104 batteries, costing 104*27.5 cents = $28.60. 6 years is $172, still less than the $200 you quoted (and, again, other cited prices are higher).
I don’t recall you mentioning a spare charger, so I guess you don’t have one. For me, once I’ve spent the money and effort to get a good pair of aids, if they’re rechargeable there’s no way I’m not getting a spare charger. On Amazon a Signia charging case is $134 and a Phonak is $175. Say it costs $150 for a spare charger. That’s the cost of 5+ years of disposable batteries just for a spare charger. So, sorry, the cost of disposable batteries doesn’t offset the extra costs of rechargeables, or for that matter the possible aggravation one could endure from them. Glad that you’re pleased with your rechargeable aids. Some of us, more and more of us it seems, don’t want them.