I agree with
@opeter.
If you consider a proprietary monotype/linotype like font license:
1. If you are creating the designs, you'll need a license. Your client and your printshop usually won't need a license.
2. If your client needs the font for his own documents, e.g. for use in Microsoft Office, he'll need a desktop font license, too.
3. If your client runs a website with that font, he'll also need a separate web font license.
4. If your client needs the font for use in an app that he releases, he'll need another license.
5. If your client gives a complete design including the fonts to you, one that you should make ready for production, chances are high, that you are allowed to complete the work without needing to buy a license. Usually you aren't allowed to use that font for other own design works, even for the client that gave you the font as part of an already finished design. That's a special use case, where you are acting like a printshop would do. The one who did the design, had the font license and gave it to you as part of open data files. But still, it really depends on the specific font license and the rights, that your client can give to you.
The less your client understands about licensing, the better it is, that all needed license fees are already covered in your quote. You offer him a package with everything included and you buy the assets, like fonts, for him.
The more the client understands about licensing, the less problems you'll have to compound with him and find a solution that fits best to him.
Small font foundries often do have more moderate conditions.
Some fonts or at least very similar fonts are often sold by different vendors under different terms.
You aren't allowed to modify most commercial or even freeware fonts. That's why I tend to use FOSS fonts more often. A SIL OFL or similar license grants rights to modify the font.
