Swimming -Drill vs duration

Do you mean "drills" or "intervals"?

Drills are usually technique drills, i.e. finger drag, catch up, etc.

Intervals are sets of shorter swims, i.e. 10 x 100 on 1:30

If you mean drills, they are beneficial, but usually don't make up more than 10% of my overall yardage.

If you mean intervals, then 99% of my pool swimming is intervals.  While you may not have a problem doing one long swim every time, you are not getting much benefit from it, other than the fact that you can swim for that distance or time.

Most (all?) swimmers will tell you that the way to become a better swimmer is to incorporate interval training into your swims.

My swim coach at our final lesson made this point...he teaches and attends masters classes over the last 20 years and he observes that the best swimmers drill the most and how strange that is as they swim fast and obviously their technique is pretty good. He notes that the slower swimmers drill the least.

I now drill 10-15 minutes every swim workout and I'm a 2:00/100 swimmer. I can really tell some drills are making a difference in my balance and breathing.

I do the same EVERY session. (And I schedule the same to the people I help)  I warm up with drills and then do my main sets. I even add some in the middle when doing some speed intervals as I notice that my form is breaking down. By doing this I get to develop a better 'feel'.

There aren’t specific drills which will benefit a swimmer the most. Drills are suppose to help with the different phases of the stroke, balance, kick, etc. but which ones can help the most will greatly depend on your technique flaws.

I know TI is great to make beginners comfortable in the water but after practicing exclusively drills, still you then have to re-learn how to “swim” and that IMO is just a waste of time. I think it is much better to get an experienced coach analyze your swim, recommend what drills to work on and alternate drills with swimming every session

We have an outstanding swim coach on our staff. She is one of the top Elite athletes in the area and has been coaching swimming for 15 years. In a seminar earlier this year she was discussing this very topic. She explained that new/beginning swimmers shouldn't do anything but drill at first. The thinking is that you need to develop good technique prior to developing endurance. Drill until your form starts to break and then get out of the pool and go home.

For the more experience swimmer, as mentioned in many previous posts, incorporate drills into your workouts and then swim afterward to get the immediate feed back. Every swimmer from Micheal Phelps down to you and me need to drill to improve economy and muscle memory.