Every font should come with a EULA (End User License Agreement) that will outline what you can and can not do with the font.

In most every case, you having purchased a license for a font grants you the right to use the font for typesetting any work you are creating. In some cases, there may be some exceptions. Some common exceptions:


some fonts don't allow you to embed them in electronic files (software or PDFs)
some fonts don't let you use them for commercial work (typically an exclusion in freeware fonts)
some fonts require an additional license for usage as a logo for large corporations (this is restriction for some of House Industry's faces)
most fonts don't let you use the font as a primary element of a retail item (for instance, using the font to create big wooden letters and then selling the letters) without an additional license. Another example is some fonts require additional licenses for using it in clothing. 
some fonts have moral clauses (for instance, not being allowed to use it to promote tobacco products)


In general, though, most fonts that you have paid a license for allow you to legally use them in logos. Just check to see if there are any exceptions in the license. If you're not sure, email the foundry and they'll be glad to answer the question for you. 

Where do I stand from a legal perspective using Helvetica Neue in my logo?
We have a list of complicated things, which the user can click on to get a new view in which they can edit all the details stored for that thing.

The edit view already has a Cancel exit mechanism (default for all our edit forms) and it has a save button (which both saves and exits back to the list).

Should the Save button be disabled until changes are made to any of the details?
