Most SaaS companies offer 30 days of trial period. I am wondering why 30 days ?

First of all, to make it clear, I don't want to give my credit card to try a product and I don't see the point why to ask for a credit card. The only thing that makes easy if you decide to buy the product at the end of the trial by simply pressing the buy button without any credit card info. It prevents lots of customers to use your product, try your product or tell their friends how great the product is. I could not use Amazon EC, because I did not have any credit card available at the time. But Amazon was in advantage than the rest, because they are big and famous. They might have a couple of logical reasons not to waste resources but if you are doing a project management application, that might be the worst idea to ask for credit card information.

If your product takes 30 days of trial to explore, your product sucks. Normally, it takes around 10-20 minutes to figure out what the product is actually doing. You might navigate all the screens, and find out how the application workflow. Here are the crucial things that I will look for in a SaaS offering;

• Is it easy to use ? Do I need to hassle all the time, or does the company realized the importance of simplicity ? 
• Does this product have the functionality that I am willing to use everyday in my work/life ? 
• Does this product have acceptable response time ? 
• What are the missing functionalities that I must/could have ?
• Who else is using this product ? 
• What is the company all about ? 
• Are they nice people ? 
• Are they writing what they think of in their blogs ?
• What is the product's roadmap ? 
• Are they going to survive through competition ?
• What is offered in the product worth the price ? 
• What value does this product offer ? ( Value - Price )

These are my thoughts when I try to rationalize the buying decision. I don't think any of the above items related to 30 days of usage. For a team setup, all the team members might give it a try in a 30 day period.

So here is my hypothesis;

If a single user is going to use the product give him a 2 day offering and let him extend the period 30-60 days with a frequency of 2 days. Thus, every two days he needs to make the decision to extend the trial period or not. The more he says "yes", more it likely he will buy the product. Than multiple the frequency with the number of users.

Pros

• Let the user say yes or no more frequently, the more he says "yes", more likely he will buy the product
• Focus on 2 days of sale per customer, engage with the customer, listen, get in touch.

Cons

• You might irritate the customer 
• Most companies use 30 days period, and saying 2 days of free trial sounds weird