I always started with availabe scripts and alter it to meet my needs. But that's long time ago. Now I'm practicing hard to do everything from scratch.

Well there's time when you have to code everything like single login to access all the tools.

Example you client want a single login system to access all tools using his/her ldap database like CMS,Poll,Forum,Email.

So this time you knowledge of programming really counts. Practice yourself to do everything from scratch. It's hard but definetely paid later.

Just my 2 cents.