Best long power reserve watches

Seiko's 6R55 gets to 72 hours while still publishing a tolerance of +25 to -15 seconds a day — a long reserve with a committed accuracy figure, in a 40mm case rated to 300m.

The $296 overhaul is published. Eight hours shy of the Swiss movements below, and ahead of all of them on everything else we score.

300m and a 46.4mm lug-to-lug in the same watch is unusual. The extender in the clasp is the detail that says Seiko still expects this one to be dived, not just worn.

The 6R35 at 70 hours in a 41mm case at 46.9mm lug-to-lug, with the ISO diver's marking and sapphire. On our scoring it ties the SPB453 for the best watch on this site.

Same published tolerance and service price as the SPB453. Choose between them on case size and rating.

This is where Seiko starts publishing an accuracy figure (+25/-15 seconds a day) and fits sapphire. A 6R35 overhaul is $296 against $176 for a 4R36 — a real difference, and one you can plan for.

80 hours is the longest reserve on any watch we cover, and the Murph puts it in a 38mm case at 11.1mm thick with a Nivachron hairspring, sapphire and 100m.

Hamilton publishes a European service price list and no US one. On reserve per millimeter of case, nothing here beats it.

Hamilton fits Nivachron across the Khaki Field line — an antimagnetic hairspring, addressing the failure mode that used to send affordable mechanicals to the bench. This is a watch designed around the twenty-year case.

A day-date complication on an 80-hour movement is the practical combination: after a weekend off the wrist, both the time and the calendar are still right.

42mm and 11.85mm thick, sapphire, 100m and a 20mm strap fitting. Same Hamilton service situation as the Murph.

Hamilton fits the same Nivachron hairspring here as on the Khaki Field line, and the H-40 runs 80 hours. Sapphire and 100m on a watch this legible is the pilot-watch specification sheet most of the category never manages.

The only 80-hour watch here whose US service price is published: $210 for a complete mechanical service, with 24 months of warranty on the work. That makes this the long-reserve watch whose running cost you can compute.

An open heart, sapphire and 100m in a 40mm case. The 21mm lug width is the irritation.

The quick-release bracelet is the detail worth paying for: this is one of the few Swiss automatics at this level you can re-strap in thirty seconds without a tool.

The Powermatic 80 in the smallest case on this page — 35mm across, 10.93mm thick — with sapphire and 100m. For a small wrist that wants a long reserve, this is the only answer we cover.

The integrated bracelet uses an 11mm fitting that is not a strap size, which we score as a fault. The $210 published service is the counterweight.

An 80-hour Swiss automatic at 35mm with sapphire and 100m, backed by Tissot's published $210 service price. The integrated bracelet is the long-term trade — an 11mm fitting is not a strap size, so you keep the bracelet the watch came with or you keep nothing.