times vs miles

When you're just starting it's most important to follow your training plan. After a season or two you'll figure out what works best for you but if you never follow a plan how will you know what does work?

^^Agree - do your research, find a reputable plan and then trust it. Training by time helps make a plan more generic and easier to apply to people of different speed. I think it also takes us away from focusing too much on distance and not enough on drills and quality of the work.

For example, a 30 - 45 minute swim could be a fairly easy mile or could be a killer workout of intervals.

You do need to be able to go the distance to complete a race but traiing for time and measuring your progress in distance should tell you wether the plan is working.

Welcome to BT!

In my first two seasons of sprints I was what many call a "random" trainer.  I didn't follow a plan but I made sure I put in time and miles.

I made sure I swam, biked and ran twice a week (each discipline).  Swimming I would do approx. 3,000 yards each time, running was usually 3 miles or more and biking was 14-20 miles.

You can be successful without a plan, probably more so in the sprint distance but when you work out, you do it solid.  When I rode, I rode hard, when I ran, I ran steady mostly, sometimes hard.  Swimming at first was just steady, I would do sets of 500 or 1000 yards with 2 min. break in between.

If you consider the sprint distance, it's only on average 500m swim, 12 mile bike, and 3 mile run.  For beginners, on average, that's 1.25 to 1.5 hours of pure cardio with 2 small segments of active recovery (transition time).

But, I must agree following a plan will get you there in great shape and it's much easier to lose focus when you have no plan.

Go by time or miles. Consistency is the key! S,B,R regularly.

Tracking time rather than miles helps take the emphasis on making X distance, or trying to think about speed. Both are especially important factors when just starting out.

technically it does not matter as both are just measures of amount of training.  generally I almost alway prefer to train by time, since I can plan my days (which are very full) and the clock uses minutes and hours.