Possible to make Summary Text longer?

Hey all!

I know there’s various plugins out there to do this, but does anybody have any idea where I can add some length to my summary text on my WordPress Blog?

I’m not interested in having the full text, but I just feel what I have now for summary text should be a little bit longer.

I’m also not interested in using any plugins for my WordPress site for personal reasons, but was just wondering if anybody knew where abouts this could be done instead of me looking through a bagillionzillion files for it 😛

Unrelated offtopic question too — but I am working on a site that is related to users getting payments from me and dealing with paypal etc.. just been concerned about the security of WordPress. I know updates are constantly coming out to patch bugs and vulnerabilities in the application. But under those circumstances should I be worried?