I don't own you!

As a photographer, I've worked with several models over the last 11 years, male and female. If you are one of the first photographers to shoot a model, you can become a little over attached to them because you feel like you were the one who discovered them. You feel like they owe it to you to model for you all the time and for free, after all, without you, they wouldn't be where they are now, right?!

WRONG.

Just because I'm the photographer that introduces someone to the world of modeling (whether for fun or for pay), they do not owe me anything but credit to the photos that I've taken for them. I have personally created a network of people (including photographers, models and stylists) that I know I can rely on because they know what they are doing and can do it well. So, in that network, I have worked with a few photographers/models/stylists numerous times and some only once. 
Models need to shoot with multiple photographers for multiple reasons. One is the obvious, DIVERSITY! If I'm the only photographer a model ever works with, they will have nice photos, of course, but it will be just one flavor and from one perspective. Another reason is learning etiquette and professionalism. If the first photographer a model works with flirts constantly, sends inappropriate texts before/after the shoot takes place and tries to use their camera as a dating tool, then that model will either never want to work in the industry again or they will think that is "typical" behavior and not establish proper boundaries. 
Sometimes when a model seeks another photographer, there also tends to be a bit of JEALOUSY in the industry. Nasty words are exchanged about other photographers. This is immaturity at it's finest, and I recommend not working with anyone who speaks down about another photographer's talent.

Here's a bit of information that photographers seem to not grasp about models:

They can change their mind!

Meaning, at one point in their modeling career, they may have shot with red shirts but now they have chosen to never shoot in a red shirt again. Who are we kidding? I am talking about shooting nudes or implied. If a model has implied or nudes in their portfolio (that I know you have dug until you found), you cannot DEMAND that they pose nude for you. They are not required to pose nude every session because they did it once or for a year or for 10 years. If a model says no, that means no. Don't harass! 
Concerning "TF" shoots: Models, I implore you to raise your standards. Sometimes, I hear you asking about certain photographers who are wanting to shoot with you (for trade) and the photos will not add anything to your portfolio. In the end, it will not benefit you and will most likely be a waste of your time. Photographers, I implore you to do your research and to be professional at all times. Models are professionals also, treat them as such. Sexual innuendos and TWSS references are inappropriate and should be discouraged by both parties during photo sessions. Above all, a photo session should be a safe place. Models should ALWAYS be allowed to bring an escort if they wish, NO MATTER WHAT. 
Concerning paid shoots: I have had a few models flake out on these types of shoots and I automatically blacklist them for myself. I will personally never work with a model again if she flakes/ghosts a paid shoot.
My personal belief about *who gets paid* for photo shoots is this: If you are a model and a photographer seeks you out, messages you and says, "hey, I'd like to use you on an upcoming project, are you available?" You have every right to ask, "What is the pay?" Just as much as any photographer can say the same to a model who seeks them out because they like their work. Of course, payment isn't always necessary or required. If the two of you mutually agree to a "TF" shoot, then that's great!

Who owns the photos? 

In general, when the shutter is released, the photographer who pressed the button owns the copyright. That means they are allowed to post any and all of the photos taken during a session. So, models, if you do NOT WANT certain photos of you posted online, do NOT allow them to be taken. Seems pretty simple but its often a very grey area with certain predator photographers who like to talk models into posing more risque than originally planned. Those photos WILL inevitably wind up being posted. Whether publicly (like Facebook) or sold on a private website. Models, be PROTECTIVE of your image. Only pose in a way that you wish to be shared. 

In the end, let's all keep a level of professionalism from every angle. Whether you are the photographer, an assistant, the model, a stylist or maybe you are just holding a light. Let's raise the standard in this industry together.