Profession skills represent training and knowledge of the skills required to perform tasks related to an occupation.
What can you do with this skill?
Do your damn job: The profession skill extends off into infinity. Anything that could reasonably be considered a profession is covered under this skill. So yay! You can do whatever you want with it.
And what exactly is it you want to do? If you’re playing Pathfinder/D&D, you want to be an adventurer. Unsurprisingly, there is no Profession (adventurer) skill; that’s covered by literally everything else. So why in the world would you want the Profession skill, and what purpose does it serve in the game?
The point of the skill is, in fact, that it covers everything else. You use it to build all of the NPCs who thoughtfully make the food, build the homes, mine the gold, and take out the trash. Its inclusion is a matter of completeness; you can point at the system and say, “Look here, we can model that.” And for its intended purpose, believe it or not, it actually works. Which doesn’t make it any kind of fun.
The skill can be used to make money; you receive half of the check result after a week of dedicated work. A 1st level pro with no natural talent (1 rank, +3 trained) can take 10 and make 7 gp a week. That’s 1 gp a day, about 30 gp a month, just enough to live slightly better than average according to the cost of living. A 5th level master, with prodigious natural talent (5 ranks, +3 trained, +3 ability, +3 Skill Focus) can take 10 and make 12 gp in a week, about 51 gp a month, halfway to living the wealthy lifestyle. Given the basic lifestyle assumptions, these numbers work as they should.
For adventurers, on the other hand, who cares? If you wanted to pretend to be an animal handler or worse yet, a low ranking city guard, why are you playing D&D? Using the Profession skill to try to make money defeats the purpose of playing in the first place. At low levels it may seem appealing, but it’s not really meant to be used by the players in that fashion; why did you learn to alter the laws of reality if you just wanted to be an accountant? So what we have is a skill that is great for filling out your background, or to simulate some fairly specific skill, but not something that too much time should be wasted on. However, many of the skills on the official skill list should be moved to Profession, because that’s what they are. Here’s a list of things that really don’t deserve to be separate skills:
Appraise (Knowing how to appraise the values of widely disparate and unrelated items is a profession, and being intelligent doesn’t make it any easier; it takes time and education combined with experience)
Disguise (Make-up artistry is an entire field. So is acting. Charisma will not make the physical disguise any better, and sometimes the point of the disguise is not to stick out.)
Escape Artist (So rarely used, and since you can take 20 on it when you’re not actively opposed, there’s no need to have this be a separate skill. Also, I taught my 4-year-old brother how to escape from being hogtied in the dark, so physical dexterity is not as important as time and patience. If you are being opposed, congratulations – you’ve either screwed up, or you’re doing this professionally.)
Handle Animal (Animal husbandry is something that professionals do, be they farmers, ranchers, or, you know, animal wranglers. And human-animal interactions are not like human-human interactions. They don’t care what you look like, or how sexy your voice is.)
Perform (Why do we need a skill like this that’s only a class skill for a few classes? Last time I checked, anyone could learn how to play the guitar, and it’s not like you’ll break the game if the Ranger can tap dance well.)
So here we have some skills that we can make Professions, because:
A: This opens up any of these skills to all classes (save Barbarians, but even that makes thematic sense), and
B: Wisdom is a more justifiably relevant ability for many of these, but…
That doesn’t matter much, as you should just use whatever ability score you think best for any given Profession. Most of them should be Wisdom based; these things are about tried and true methods of doing things, and the patience to perform certain tasks repeatedly. In most cases, a professional doesn’t have to be smart, or have a sparkling personality, or be strong, they just have to show up, know what they’re doing, and have the good sense to do it without screwing around.
When the PCs take a Profession skill, do them the justice of assuming that they’re professionals. Even one rank in a Profession skill deserves respect. Don’t waste time rolling for trivial things, and don’t assume that a failure is some earth shattering event (unless it’s supposed to be, like, say, Profession (bomb disposal). Which is probably better covered with Disable Device.) If a player wants their character to have one rank in Profession (cook), then just let them cook tasty meals at will. They may not be the greatest chef in the kingdom, but a failure doesn’t mean an inedible mess; it means that they cooked a less than satisfying meal, or they had bad ingredients, or what have you. Unless they’re cooking for the king, who cares about the occasional failure, and why are you having them roll to cook dinner anyway? The roll is there for truly important moments, like the half-orc fighter impressing the embodied avatar of Sarenrae with his secret Five Demon Chocolate Chile con Kobold Carne. Delicious! Anything with less gravitas isn’t worth the time spent shaking dice.
Final Analysis: Profession is great for background, and for skills not too often called for, or relevant to the adventurer lifestyle. If a player wants to be a master of Profession (cat wrangler), then go ahead, let them take it. It’s just as good, however, to let them have it for free without wasting valuable skill points on such a thing. In fact, I would go so far as to say that any character who wants to should get one rank in a Profession skill for free; insofar as that’s likely to be worth jack squat in the grand scheme of things, and if it is, so what? There’s nothing better than a good backstory when it comes to getting a grip on playing a character; so if the party sorcerer wants to also be a trained ballet dancer, let him. Some professions are more useful than others, of course, but even one free rank in those isn’t game breaking. Rare is the person who hasn’t learned some useful skills during their upbringing; and you can always tell who they are, people call them gamers. So use Profession, don’t be as much of a hardass about it, and maybe your players will surprise you. Or don’t, and you’ve lost nothing. It’s as simple as saying, “Yeah, my character knows how to groom dogs,” and writing it down on a sheet somewhere. Go crazy.