It's just as easy to hit [ CTRL + ] as it is to hit backspace. If you are worried about your users' ability or knowledge, then you can simply include a link that says "adjust text size up / down" and let them click that to get the desired effect. Browsers allow users to customize the font for a reason. It's impossible to claim a default size that everyone is going to like.
It gets pretty tedious, when you are doing this for 80% of the sites you are visiting.
Also on slower hardware - zooming is a drag, and it can be slow.
The browsers do allow for customisaton, and I think this is probably the easiest thing for an end user. I use a minimal font size of 16px, and that works for me. But it does break some sites - Facebook's layout has been broken over the last month like this for example. Which is fine if you kind of understand the reason for it, but could confuse other users. Just as some navigation breaks, think of horizontal nav, that falls onto another line when the text size increases - I'm thinking hover states, and drop down menus.
Just as most users don't know about Ctrl+, most users wouldn't know what "adjust text size up / down" meant either. My 60 year old father uses the Internet a lot, but he wouldn't be able to identify your use of the word 'text' with the words he reads on a website. Up or down to him would mean scrolling.
That's interesting. How else would one describe the words that you read on a website? It's text. Or copy. But text is probably more universally understood.
If he were reading a magazine and you said "do you find the text to be too small", you think he might turn to you and say "what do you mean by text, I'm reading a magazine here, there is no text."
