Guaranteed time accuracy twice a day only if used with battery removed.
Those mechanicals with COSC certificate aren't that hopeless. Some years back I want to get some Jojoba and heavy book ends to local TJMax. I walked out with those and automatic wristwatch with Swiss chronometer movement. It was plorearian ETA 2824-2 yet it gave 24 hour gain of only 4 seconds. Never expected to see something like that there but the watch was new and price of less than $300 so I bought it. Some real good mechanicals like Patek can have gain of only 1 to 2 seconds per 24 hours.
