Do you make your own training or follow one given to you?

I am just curious to know about your training. Do you just go by feel and make your training as you go or do you follow a plan given to you by a coach or one found on here or anywhere else on the internet or book?

Myself, I go a day at a time and decide what I will do that day, however I do some reading and try to aply some of the tips provided. I listen to my body and try to vary my workouts a bit. I will try to get about 3X each sports per week (about 9 sessions in one week) to balance everything. I might do a little more biking because I also do mountain biking, well actually mountain biking is what I do and triathlon comes in second (will do my first one this summer).

I monitor my heart rate and try to listen to my body as much as possible, will normaly take one day off per week but if my morning heart rate is 2 or 3 beats more than what it should be I might take an extra day off or do some light spinning for recovery.

I try to train in my aerobic zone as much as possible when spinning and running (a little lower on 2 hours spinning sessions).

Swimming is a new sport to me so I'm still learning, I am trying to build up on it, trying to just do the laps without focusing too much on time but rather distance. Trying to add more laps non stop ect..

So given my situation (good backround in biking) and somewhere in the middle for running it is hard to find a training plan that suits me. If I was to follow a 20 week program to complete an olymptic distance then the first weeks would be way too easy for the biking part and would actually be counterproductive for me, running would also mean cutting back a bit on my time..

So I continue to do my own training and go by feel. This means I continue to add the milleage on the bike that I am used to, as well as running and get a swim workout at a begginer's level trying to get more done each week.

P.S I train between 8 to 10 hours a week, I wanted to try a sprint triathlon at first but now I think I will do an olympic distance because I like the 40K bike part better than 20K and the 10K part of running as well, I see it more chalenging and I believe that with the amount of time that I put into it an olympic distance seems to be the right distance to go for..

Any thoughts?