Can't say it's been a problem with mine. I might go weeks without a reboot. The only time it's rebooted is a firmware update or loss of commercial power. That hasn't happened in a long time.
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In fairness, it isn't used heavily, but it can sit there untouched for a week and works just fine when I do use it.
Dan
Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.