I've kind of ranted before about what I consider to be the myth of needing dedicated equipment for sours. I brew quite a few sours, but also lots of clean beers. I really think the idea of dedicated equipment probably originated in order to address the lowest common denominator...the brewer that doesn't clean and sanitize sufficiently. Wild yeast and lactic acid bacteria are all around us...they don't exist only in vials and smack packs of sour beer blends. Unless you store your equipment submerged in vats of sanitizer and only remove them long enough to use them for brewing, they've already been exposed to brett and bugs in your environment. Try leaving out some wort overnight and you'll likely see signs of fermentation in the not too distant future.
All that said, I think there are some pieces of equipment that do make sense to get a second set...for me that means equipment that can't be fully disassembled and/or boiled/steamed, so that's more or less limited to autosiphon, bottling bucket, and bottling wand. Autosiphons have parts you can't take apart...same with bottling wands. Bottling bucket valves can be taken apart, but they are usually made of softish plastic that can't be boiled or scrubbed without damaging the surface.
The rest of my equipment is shared between clean and sour/wild beers and I've never had a problem. For hoses, get silicone; it will pretty much last forever and you can boil after using to transfer a sour/wild beer. Re fermenters, I use a mix of glass carboys, plastic carboys, and a stainless conical. Glass is easy to clean and sanitize. Stainless is easy as well and things like ball valves and racking arms can be boiled to sanitize. As long as plastic is in good shape, it's cleans and sanitizes well; if it's not in good shape, it should be retired regardless of whether or not you brew sours. Bungs can be boiled. For pulling samples, I use a stainless turkey baster that can be boiled to sanitize.
Some things that I do to ensure I don't run into problems, I clean and sanitize equipment before and after each use. This helps prevent any critters from establishing themselves. I also use both iodophor and Star San in my brewery. Often I'll alternate between them, the idea being that if there is a culture that's resistant to one sanitizer, it's not likely to be resistant to both.