The first problem you encounter when you decide to go hero is inevitably the uniform. First, should you have one? I feel the answer is almost always, "yes." For one thing, a uniform is essential if you intend to maintain a secret identity. The masks and stuff may seem silly to some (believe me, it sometimes seems silly to those of us who wear them), but if you care about maintaining a normal life apart from your hero identity, it's a must.
Second, a good uniform, whatever the cosmetic design, is going to offer you protection. For guys like Wolverine or Luke Cage this doesn't really matter, of course, but for the rest of us it is of primary importance. I'm tough, and I heal pretty quickly, but that's different from being invulnerable, and a well-placed blade or bullet can put me down for good just the same as anyone without powers. Lightweight carbon-polymer or ceramic armor is a must for most of us. It's not fool-proof by any means -- no armor can protect every inch of your body, and even the thickest parts of the armor can take only so many direct hits before it gives, but if you live smart it can give you just the edge you need. My stuff happens to be custom-designed, thanks to my genius brother (I'm not just bragging here -- his IQ is seriously off the charts. It's possible he's powered as well, just with a super mind instead of a super body. It's not uncommon for this sort of stuff to run in families, after all.), so it's a lot lighter and more flexible than most stuff out there, but anyone can order really top-notch body armor from a handful of military distributors. A lot of heroes design their cosmetics on top of just that kind of off-the-shelf military-grade shell. 'Course, that stuff isn't usually machine washable like mine, and it costs a fortune.
But while protection (for your identity and your body) is necessary for most of us, the primary function of a hero's uniform is identification; the uniform serves to separate superheroes from regular folks with just a glance.
This is more important than it may initially sound. Superheroing is a dangerous business -- for us, for the "bad guys," and for anyone who might happen to be around us. Let's say something bad is going down -- a mugging, say. Now, I'm a good-sized guy: over six feet tall, nearing 200 pounds, and in good shape. If I step up and try to take control of the situation -- you know, stop the bad guy -- he's gonna size me up. Yeah, I'm a big dude, but I'm just a dude, and someone desperate enough to mug another person is not going to stop just because I say so. Even if I threaten bodily harm, and let him know that I am super strong and fast and I will kick his ass, the mugger will likely ignore the threat, or even turn on me. If I'm wearing rugged, protective clothing (like, say, a motorcycle jacket), he may look twice and factor into his equation that I could be tough, which will reduce the chances he'll ignore me, but not by a large amount. He'll still likely finish his job (or try to), or pull a knife or a gun on me, and I'll have to hurt him.
However, if I arrive on the scene in a costume which says, unequivocally, that I am different from regular people, more powerful -- super, if you will -- the story changes. The bad guy, identifying me immediately as a superhero (even if he doesn't know which one), is far more likely just to give-up, or at least not put up so much of a fight. This is especially important when dealing with a handful of thugs. One lone guy without superpowers or extensive training or a very big gun is unlikely to pose a lot of danger to me. But three or four guys is a different story. It all comes down to intimidation. Three or four guys with guns or knives or whatever and trouble on their minds are never going to back down from one interloper in jeans and a t-shirt, or even a motorcycle jacket and combat boots, no matter how big and scary he is. But a superhero is a different story. Even if, collectively, they decide to take the huge risk of tussling with a superhero in costume (and most won't), their collective confidence will be eroded, and they'll be easier to deal with.
I call it the "Luke Cage Problem." Luke's a big, scary dude -- at least my height, bald, goateed and bulging with muscles. I met him at a party once in the late 90's -- a nice guy; intense, but nice. But he hasn't worn a costume since the late-80's, and even then it wasn't a very clear superhero-ey thing (a shirt unbuttoned to the waist and gold wrist cuffs -- more a disco-revivalist statement than a uniform). He trolls the worst New York neighborhoods, and guys are constantly stepping up to him because, as far as they're concerned, he's just a man, just another citizen to victimize. They don't face him with fear in their hearts, so he spends way more time actually fighting than he should have to. He's Luke Cage, for chrissakes. Power Man. The dude can punch through steel, and his skin is functionally impenetrable. If he wore a label of some kind advertising it, he could bust up a gang fight with a glance. Instead, he has to wade in, throwing fists, and round up the unconscious bodies for the police afterward. Even an unknown like me, dropping into a LA gang fight in costume, is gonna have a certain percentage of those tough kids just surrender, or at least throw down their weapons and bolt, leaving a reduced number of really dangerous types behind. When that happens, I know on whom I have to focus my efforts, 'cause the not-so-dangerous guys already got outta Dodge. And those hard guys who are left over are gonna come at me with lumps in their throats, because they know that there is something special about me which makes me wear this costume, something far more dangerous than my slim frame suggests. I won't have to go all-out, flipping-over cars and maybe even firing off an energy bolt or two to get everyone's attention, which saves me potential harm, the bad guys potential serious harm, and potential collateral damage to property and, god forbid, bystanders. Like I said, Luke's functionally invulnerable, so he's not so worried about his own skin as I am, and maybe he just really enjoys the tussle, but those of us who don't have skin off of which bullets and knives just bounce have to be more careful.
Plus, providing you're not carrying to much extra bulk around your middle (a story for another time, my friends), a good uniform just looks cool. And I'll tell you something most heroes would not be willing to admit: if you wanna make a mark in this business, if you wanna brand yourself for posterity, you've got to look cool.