I'm comng up on my first serious FTP and VO2 Max power tests. I've been thinking about where to do these, and the following come to mind:

1. Indoor trainer -- Very easy to repeat all the conditions of the test every time you re-test. But, probably pretty difficult to get and keep the effort at VO2 Max for the duration of the test. (Am I right there?)

2. Outdoors -- Find a big hill and the VO2 Max effort will be easy to attain and maintain. But, very difficult -- maybe impossible --to get good repeatability of testing conditions (wind, temperature, traffic, dogs, sun/cloud/radiant heat, etc.).

For those who train with power and who are serious about getting good test data -- how do the plusses and minusses balance out? I like riding outdoors better, but "like" doesn't necessarily get you the best data. If you have a choice, what do you do?