Depending on the time you have you may also want to carry food and drink. When I spend a day on the river I would usually take lunch, a small billy and gas cooker if the area to be fished was in a fire restricted area. Also wet weather gear and spare clothing in the way of light weight but warm polypropelene shirt, socks and leggings. All of this gear requires a serious, good quality fishing vest.

Not only is the fly fishing vest a great way to keep organized, but also ensures that you have everything you need. By setting up your vest properly you can leave everything inside ensuring that the next time you venture out everything is where it should be. Get used to having the same things in each pocket so you can instinctively find whatever it is you need. Most vests these days have a multitude of pockets and compartments for whatever it is you need. Camera pockets, cell phone pockets, sunglasses, sunscreens, the list goes on.

Everyone will have need for different vests for fly fishing. Also for the many women who now enjoy fishing with the fly there is a range of womens fly fishing vest readily available. Myself I have two, one I use for fishing from a boat, canoe or where i know what to expect such as local lakes rivers an streams. This is a lighter trout fishing vest for basic gear such as fly boxes, leaders, a spare spool, and various tools. On the other extreme is a full day pack / vest that can accommodate various reels, lines and equipment for a long day hike.
 
Obviously the fishing vest you choose will suit your style of fishing, be prepared to spend a little extra and opt for quallity fly fishing vests such as a simms fishing vest. Not to leave out the many women who now enjoy fishing with the fly is a range of women's fly fishing vests readily available. Like the rest of your fly equipment good quality gear will give years of enjoyment and fond memories.