Good Clothes are a BIG help.
There are some very expensive survival clothes / coats / shoes out there. Don't by designer names for the sake of it if the quality is much the same as usual products, go for items that are simply good designs. Of course teens will insist on designer names just for the kudos. Paying massive prices just for designer names may drain your cash you could buy a genuinely good survival item with (like a sawyer water filter or tenacious tape) and yet leave you no better off in real survival terms.
The quickest way to die in survival situations is of exposure to the elements. The thing that is most likely to kill you is not a bear, wolf or a mountain lion, in fact (as Bear Grylls pointed out) statistically eating the wrong snails is more likely to kill you than any of those! It is:
SNOW & SLEET
or a combo of any of the above that is most likely to kill you, after that floods, forest fires, avalanches and landslides are a big big danger, but it is the WEATHER itself that kills more people in survival situations than any wild animal, so having the right or even the perfect clothes is the first line of defence and for increasing your survival chances. Natural disasters fuelled by the weather like flash floods kill massive numbers of people. I remember seeing an oasis in a desert and thinking it would make the perfect hideout from the 666 System, until I learned the oasis itself was the result of flash floods that happened often in that area!
If you end up begging for food on the streets because all you plans to avoid the 666 mark fell through, if you are dressed in more expensive new looking clothes than those passing by, they might be unlikely to help you. That is about the only downside I can think of when having good quality well chosen clothing.
A friend of mine bought a pair of trousers for £350 (and then it was in a sale!). It was a pair of Arc'teryx expensive waterproof trousers that Bear Grylls once wore in an episode of his TV survival series. I am not suggesting buying them as he had trouble getting the pair with the best braces for him etc. I bought cheap waterproof over trousers, but if I hiked in them I got soaked in sweat (big danger in cold weather). I tried his Arc'teryx trousers and I never sweated a lot hiking in them. They also had such quality about them, and felt so expensive and well made to the touch. Can such expense be justified? On my budget the answer is no. Sometimes you will pay twice the price for a product 10% or 20% better. Sure that could mean the difference between life and death in extreme situations, but in the big picture of all the items that can help you, is it worth it? When there are so many gadgets and products you could otherwise afford? You might wash the expensive clothing wrongly or damage them. It's you call..... try to have common sense.
Try stuff out.
Tried and tested things are best, not just for clothing. I remember ordering a really great looking pair of gloves, that looked "so survivalist" but when I went out in them they looked cool, but my hands were very cold in them. It is no use buying things that just have a reputation for being good, without testing if they really are good for you as an individual. This is one way shops are better than online, you can get to try something on, or see it in reality instead of just photos.