Greetings and welcome to the forum!
In the grand scheme of things, apps take up very little space. By far, the biggest disk space hogs are videos. These can run 1gb or more each!
When you plug your iPad into iTunes on your computer, you will see a graphical representation of the contents of your unit. It is not the most current usage graphic, but here is my 16gb iPad --
I have over 800 songs, some of which are full length symphonies so they take up quite a bit more room than and "average" song. If I played all the music on my iPad, it would take almost 3 days!
As far as videos, I only have 1 full length feature film (
The Hunt for Red October if you must know!), one 1/2 hour TV show and a few YouTube videos and you can see how much room this small number of videos take up.
Photos... I have nearly 1000. Depending on the size and format, the don't take up much room.
Apps... I have over 60 and honestly, I could cut that number in half and not miss any of them.
Personally, I am not worried about running out of space any time soon!