There is a strong argument that many people hear alarm bells when asked for a credit card for a free trial. Yet, there is a valid case for wanting to overcome people's inaction, where people just don't bother to sign up (some of whom would actively enjoy/benefit from the product if you could persuade them to look deeper).

I wonder if there is a model that goes someway towards addressing both of these:

1) One month free. No credit card required.

2) Another month free (with more 'credits' or whatever), if during that first month you supply your credit card details. You will automatically be renewed if you don't cancel, but are free to do so (and will get reminders).

In this way, people get to try the product without alarm bells. They get something in return for demonstrating their interest, by way of more free time and you giving them access to more 'credits' (monitor more servers, look at more profiles, whatever it is).

This helps overcome their inaction, but avoids the alarm bells. Not sure how well it'd work but would be interesting to see.