Seeking productivity tool that enforces realistic time management

https://kanbanflow.com/ might work for you. It's organized around real-time tracking (Pomodoro-style), but you can just enter in the time spent manually and avoid that feature. It does have the ability to put in "estimated" times, which might help you set up target hours, and it allows you to limit the number of items in any given column, but it won't (at least in the free version) warn you if you've tried to put more than 8 hours worth of tasks into your "Do Today" column, for example. Because it is based on a sticky-note organizational system, it is limited in the extent to which you can break down tasks. Tasks can have subtasks (an unlimited number) but not subsub tasks. Currently, my setup has columns for To-Do (basically a grab bag), Do This Week, Do Today, In Progress (limited to 3 items), and Done. I use colours to differentiate between work, school, and home tasks. I'm not really strict about the delineations between the Week, Today, and In Progress columns, but I do try to keep them "clean" so I have a good idea of what is top of mind. I work in a job where I need to keep track of my time by 0.1 hour increments, so I do use the Pomodoro timer and real-time tracking feature a lot of the time. Sometimes though, I will just manually click on a task and change the time (like, if I ended up pulled into a meeting regarding Task A, I could go back and add that). The manual time tracking is not perfect, and it's lacking in reporting features (I don't know if the pro version is better), but it beats trying to keep track of things in a notebook.

http://www.liquidplanner.com/ is awesome for its flexible scheduling engine, and does (I think) everything you're seeking, but it might be a bit of a sledgehammer. I've used a combination of https://www.toggl.com/ and https://en.todoist.com for my personal time tracking, but it's not nearly as effective as LP.

Hm. The Emergent Task Tracker is cool and closer to the level of simplicity I'm looking for, but my ideal solution here is so simple that I never have to set a start time or log things by time of day. Looking back retrospectively and seeing "oh, I spent 2 hours on thing A on Monday, and then none until Thursday when I spent most of the day on it" would be cool, but anything beyond that isn't just overkill, it's dangerously distracting. Michaelh memailed me a good Google spreadsheet prototype that may be the way to go. Maybe if I log enough time learning Python I'll be able to build something closer to what I want eventually...

Do you want to avoid the ability to break things down into "projects", setting exact start & end times, etc. Or can you live with the functionality being there without having to be used? I've been using https://www.toggl.com/ for tracking time. It would work just fine if you just entered a title in the tracker box, a time amount in the time box and hit the save button. There is a paid plan, but everything you need is in the free version. Time entry works either as minutes or as hours. So you can type in 90, and it'll read that as 90 minutes. If you use anything with a period in it, like 1.5 or 2. it'll parse that as hours. I think the normal use case for them is real-time tracking, but if you enter a time amount before saving it won't start the timer and just save what you've entered. If you do go for this I would probably suggest making a "project" for each of your activities and then track time on the projects skipping the description. I think this would make it easier to see the breakdown in the reports pages. They have web, android and iOS. So you can pick what suits you. Or switch around.