Initially they will end on a website (likely right here). If the images become good I might offer to sell prints, or at some point make an exhibition or even a book, but I make pictures because I like to and that's about it.

It depends on the kind of agreement we make:
I always work with a model contract.
Always!
This states I will always retain all usage rights for the images which is necessary for me to sell prints (selling is commercial) and making exhibitions and marketing materials around this. Therefore I use a standard 'all rights' contract which essentially means I have full rights over the images and can do with them what I want. If I can sell the images - good for me if not - too bad for me. Other than the initial agreement (TFP and/or modeling fee) you will not recieve any reimbursement later. If you want to pose specific limitations in how the images can be used we can usually work something out, but I need to know very early in the process if this is the case. There is a lot of time and preparation going on in coordination a session, time involved while shooting and a LOT of time selecting and retouching images afterwards. I need to know before committing to a session in order not to waste a lot of time. I'm sure you will appreciate this if you consider it carefully.

It depends how many good images there are from the session. I like to finish images off to a very high standard. This means that I routinely spend between 1-4 hours retouching every single image. Normally from a 4-6 hour shoot I will deliver between 3-5 images from a TFP session to the model. Normally my models first comment when they see the images is a derivative of WOW. I strongly believe in quality over quantity, that is I prefer to make one very good image from a session available rather then 10 mediocre and not properly retouched images. And for TFP/TFCD jobs I don't mind making physical prints of some of the images either. While I will strive to edit images fairly soon and perhaps make a webgallery so the model can have a look at the images from the session, it will likely be a matter of several weeks before I'm able to supply finished retouched images depending on workload.

Most models have certain things they are not comfortable participating in, or certain kind of pictures they are not interesting in publicising. I never try to make models do pictures they are not interested in doing, and I always respect personal limits. I do prefer to know these in advance as I often have a very good idea on what I want to achieve in a certain session. Knowing personal borders in advance often makes the difference between a good session where we both are comfortable with what we do and one where you as a model feel I try to make you do something you don't want to do.

A model that constantly says NO when asked to pose in a certain way is not a dream scenario for a photographer, and a photographer that constantly try and push limits can be annoying for a model, both are mood killers. Limits are fine, but let's get them out in the open in advance so we can enjoy the session and make pictures we both like.