Will it stay on standby mode all the time if I don't turn it off?

If it's under standby mode more than 10 mins, it (L11 robot vacuum cleaner) will get into sleep mode. Under sleep mode, all the indicators will be off, you can press any buttons to wake up the vacuum cleaner.If it's under sleep mode more than 12 hours, it will be off automatically(but it will not get into sleep mode while charging).