「我 83% 该换电池吗」在论坛永远得不到有用回答，因为回答的人不知道你的衰减速率——同样是 83%，用了 1 年和用了 3 年是完全不同的两件事。
填三个数（当前健康度、循环次数、购买日期），代码算出别人回答不了的那部分：按时间的每月衰减率、按循环的每次衰减率、你的实际使用强度（每月多少次循环），然后按这个速率外推什么时候跌破你设的下限。
再把换电池报价和换新机预算填上，它把两者摊到每月做对比——这才是这个决定真正的形式：不是「值不值得」，是「每个月为这台机器付多少钱」。
最后给四件让它掉得更慢的事，按有效性排序。排第一的不是充电玄学，是别让它发烫。
"Should I replace at 83%?" never gets a useful answer on a forum, because nobody there knows your degradation rate — 83% after one year and 83% after three are different situations.
Enter three numbers (health, cycle count, purchase date) and the code produces the part forums can't: percent lost per month, per cycle, your actual usage intensity, and — extrapolating your own rate — when you'll cross the floor you set.
Add the battery quote and a new-phone budget and it puts both per month, which is what the decision actually is: not "is it worth it" but "what am I paying monthly for this device".
Then four things that slow the decline, ranked. The top one isn't charging folklore — it's heat.
按你的症状判断是电池问题还是别的老化、官方换电池与第三方的取舍（保修、防水、健康度显示）、二手残值的现实估法、以及换机的话什么时候买最划算。Whether your symptoms are the battery or something else, official versus third-party replacement trade-offs, a realistic view of resale value, and timing if you do upgrade.
本工具不做设备诊断，也不预测故障。 所有结果都来自你自己填写的三个数字，按已发生的平均速率做线性外推——而电池衰减实际上是非线性的，且受温度、快充频率、充放电区间与个体差异影响，外推只能当量级参考，不是预测。系统显示的健康度本身有误差，可能因系统更新或电池校准跳动。是否更换、由谁更换请以官方或有资质的维修方检测为准；非官方更换可能影响保修、防水与健康度显示。若出现电池鼓包、异常发烫、漏液等情况，请立即停止使用并送修。你填写的内容不入库。
This performs no device diagnosis and predicts no failure. Everything derives from the three numbers you enter, extrapolated linearly from your average rate so far — real degradation is non-linear and depends on heat, fast-charging, charge range and unit variation, so treat projections as an order of magnitude, not a forecast. Reported health figures carry error and can shift after updates or calibration. Rely on an authorised or qualified technician for whether and how to replace; non-official replacement may affect warranty, water resistance and health reporting. If the battery swells, overheats or leaks, stop using the device and seek service immediately. Nothing you enter is stored.