Side (Pack) Pockets

Right side. Water

Left side. Beer, occasionally, trekking and shelter poles.

Seriously.

Some trips they get hardly any use during the day.

I like my stuff inside the pack.

I do not need very much while underway. Don't use hip belt pockets much either.

I've never gotten the 'hang' of side packets.
Mine are usually empty.
I can't reach back that far to get my water bottle while hiking :(

Billy

Side Pockets are pretty much indespensible.
Water in one side and stove/fuel in the other. The front pocket is pretty much food, rain gear, maps, steripen, and folded platy bottle.

Left: 1 liter water
Right: 1 liter water

left side I put my packrod and a .5 liter Platy, right side a 1 liter Platy- stretch side pockets are nice and roomy on my Exped

I don't see why you would ruin a perfectly good pack by putting side pockets on it : )

Water is best put inside where it will stay cool better.

Other things that I would want while hiking can be put on top of main compartment.

Side pockets stick out and can snag on branches or rocks. Require extra fabric and sewing – better to just have the right sized main compartment.

Aesthetically, I'de rather have just one pocket.

Side pockets are left over from days of old when I have big pack and carried too much stuff.

But that's okay, you side pocket people can do what you wish : )

water
fuel
snacks
map (depending on how secure it seems — depends on map itself, and how loaded up the pocket is)

Basically:
liquid
things I want quick access to, but are too big for a waist belt pocket

Left side: Tarptent Contrail
Right side: Water bottle

(Snacks & camera in hipbelt pockets. Sunscreen, deet, sanitizer, & Mora in harness pockets. Weather gear in front pocket. Other ditties in top pocket. Sleeping gear, feed bag, and Platy inside. Maps, wallet, key, phone, & lanyard with emergency thingies in pants. Come to think of it, I have a lot of pocketses!)

Pockets in general turn a pack into a trail office. You are living on the trail and those pockets allow good organization and quick access to water/filter, snacks, latrine kit, sunscreen, bug repellent, camera, notepad, bandana, sit pad, map and compass, rain/wind shell, gloves and whatever else you don't want to dig out of the bottom of your pack every time you need something. I prefer side pockets and water bottles vs internal bladders and hose.

+1 on big long pockets for "impossible" objects like fishing and tent poles and tripods.

Left Pocket:
REI Flex Lite Chair
Silky Accel 210 Saw
Reflectix sit/food pad

Right Pocket:
2L Platypus
1L Smartwater Bottle

My side pocket content changes between trips. I have a ULA Ohm 2.0 and the side pockets are pretty cavernous, so I don't have to be too selective. From my last trip, going by memory:

Right pocket:
– Fuel canister (partner carries stove & small canister)
– 1 L Platypus soft bottle (only filled if on a long waterless stretch)
– Tent stakes in tyvek (FedEx) envelope
– Lunch items for the day

Left pocket:
– Ziploc with T.P., soap, other personal cleaning supplies
– Ziploc w/ emergency items (firestarters, tiny multitool, keychain LED, 30m cord, pad repair)
– Sol Emergency Bivy (re-folded flat)
– Polycryo ground sheet in sandwich Ziploc

Before that trip I used to have a 32-oz. bottle with an energy / electrolyte drink in the right pocket. I omitted that and went with chewable energy on this last trip (Perpetuem solids). Those were effective and convenient, but foul (like chewing play-doh). I'm going back to the bottle so there will be more gear juggling.