I recently purchased a mint condition Tutima f3 with the Lemania 5100 movement. After two weeks of constantly wearing the watch, it still seems to gain or lose up to 5 seconds a day. Although this seems to be well within standards, it seems odd that sometimes it will gain time and sometimes lose time and is not consistent given that I wear the watch for the same amount of time each day. I figured this is probably just due to the settling in period though, as lubricants are dispersed etc (despite being pre-owned, I don't think the watch was ever worn previously). My bigger concern is that, twice now, the watch has stopped while off my wrist at night. My understanding is that the Lemania 5100 has a power reserve of 40 hrs once fully wound. Both times the watch has stopped were after days where I spent less time walking around than usual, but given that the watch should at least have been fully wound the day before, it should still have been within the 40 hr period. Additionally, I was wearing the watch for the entire day prior to it stopping at night. Even if I wasn't walking my usual 2+ miles that day, it seems like my activity should have been sufficient to keep it running for the 8 hours it was off my wrist. Any thoughts? Is this something I should be concerned about?