While working on my startup, should I keep track of my time?

Yes you should track your time.

As a startup founder time is your most precious resource, the startup success is largely dependent on how you spend your time.

Time tracking will help you eliminate time wasters (both things you shouldn't do and things its more efficient to get someone else to do for you) and improve your estimation skills (by comparing the time it actually took to do something to your original estimate) - those two alone can improve your efficiency so much its worth all the trouble of time tracking.

The important thing about time tracking is that you need software that tracks your time as you work, software that requires you to fill a timesheet after the fact is worse than useless.

disclaimer: I sell time tracking software, obviously I think my product is the best time tracking product ever made, I won't link to it here because is feels spammy but I'm sure you'll be able to find it if you follow the link to my blog in my user profile.

I started using https://www.rescuetime.com/ a few weeks ago to just get an idea of how I spend my time during the day. It just records what app/webpage has focus for how long. It then has a default list of how productive each app/website is which you can refine. You can also group apps into tasks e.g. software development. You then get a report on both your productivity and the time spent on each type of task. Best of all it is all automatic.

+1 for rescuetime. I have tried some apps in the past, I found this to be least bothersome and does it job nicely.

I have a system to track my personal hours, but sometimes, on busy days its too much work to really track your hours.

Outlook's journal is good, I try to update what i do daily on a white notepad i keep next to me. (Pretty much checklists), and when i make a call, or work on something i write a little note. At the end of the day, i try to get this into outlook. The reason I do is not to keep track of my time per say, but more to be able to look back to when what happened.

Tracking your employees time, is a little more important than tracking your own. If you know something like a girlfriend, wife, cell phone, tv, whatever distracts you then you need to look at your work environment. If you spend too many hours on the net, limit your browsing time (there is a good google chrome plugin for this).

Bottom line dont sweat it too much. Only should be worried if you are cheating yourself and goofing off.

Time tracking can be really useful, if you can find a way to do it that you will actually follow through with consistently enough to yield useful info, and if you can find an efficient enough way to do it that the time tracking itself doesn't become your time-waster.

I found for a long time that time-tracking was too distracting to my workflow to be of any use, however recently I started using emacs org-mode for my notes and to-do lists. Its integrated time-tracking seems to do the trick for me.

It may be more useful when it comes time to hire employees/contractors to take over some of these tasks. Measuring time can also aid in determining if you need a full-time or part-time person. You will be informed and have the flexibility to manage by task instead of just time.

You may want to have someone else track your time or track projects together with your team. Sometimes you're too nose-deep in your own work that it's hard to see how things are progressing overall (and how they should be progressing).

Contrary to some of the other posts here, I would say that tracking is not a waste of time - that is if you improve your current work efficiency. Schedule your work in weekly iterations and take one day out of each week to reflect and plan. Perhaps most important is coming up with a minimally viable product to release every week. Have you ever thought of using SCRUM?

I use it, and it helps everyone stay motivated because we have a visible product we can proudly say we completed within the allotted time. More importantly, we learn and improve our processes every iteration. It's all about self-improvement - if you can do that, the benefits spill over to everything else you do including your startup's transition to a larger company.

One of the comments about time-boxing rings true for certain types of tasks. While a startup may require you to wear multiple hats at once, you should try to reduce multitasking as much as possible. Research shows that it significantly reduces efficiency if you work on more than two tasks at once. Break down your work into discrete tasks with clear acceptance criteria - try not to work on other tasks until those are done (unless there's some kind of emergency).

Btw, exercise is a good idea. Like it or not, people can and will judge your business based on how healthy its members look.