Losing things is more serious than me... I'm more of easily forget things ... If this is your case, i strongly suggest u to look for an app call "Todoist". It's basically a todo app la but it's really good and easy to use and can sync with pc and your mobile and tablet and whatever things. Once ppl tell me to do something, or i want to do something, i will write it down together with the due date so will never forget.

Can categorize to personal / work. can have widget on your screen. Will sort according to date. Every morning i wake up I know what to do for today.

Give it a try hope it help u.