Since this is an article about hiking, I'll first show you what happens when you like to change lenses on a hike in dusty, desert conditions.  Then we'll have a look at the modernization of my hiking gear as the years roll by.  Let's start it off with a few before and after shots of the sensor on my Sony A 100. 

In the first image, taken at F/11, we see a dark blob in the upper center.  This is a good indication that your sensor needs cleaning.  Although easy to fix in Photoshop, I'd prefer to take care of the problem at the root.  

Blob in upper center.

In the next image, I pointed the camera at the clear blue sky, and fired off a shot at F/40.  I enhanced the view by desaturating and setting the levels to: Shadows, 90, Midtones 2.00, and Highlights at 120.  This just makes it easier to see all the specks.

This looks pretty bad, but to be honest, I wouldn't have noticed any dirt at all if it hadn't been for the big speck in the middle, visible at F/11, but not visible at F/5.6-F/8.  At F/16 and smaller, lots of dirt will start to show.  Who shoots at these apertures anyways, much less F/40?

It's no big deal to fix the dirt in Photoshop, and no big deal to fix by cleaning the sensor.

Enhanced to show every speck.

Clean enough.

Some people are afraid they'll ruin their camera if they try to clean the sensor, and typically don't have much confidence in themselves.  If you're this type of person, don't clean your own sensor, send it to the factory where it'll take a kid two weeks to run a brush over it.  It takes me about 3 minutes from the time I gather my blower bulb and brush, to the time I re-install the lens and go out shooting again.  I've done this a hundred times.  My cameras are in the same good condition as the day I bought them.  To see my article about sensor cleaning, go here.

Now let's move on to some hiking paraphernalia.

In the olden days, my hiking accouterments included; a hat, a jug of water and a stick, that's it.  Now days, in the age of appropriate and reasonable behaviour, up to and including loss of income, (read dehydration, fall, medivac etc.) one does not just sip water while sauntering in the wilderness. The photo below indicates my only necessity in the olden days--though not normally "purified" water, I just had this on hand for the shot.  The photo below this one is a little more complex, see accompanying text at the bottom.

This is what I'm required to carry now.  Starting from left to right we have:
 
Sunglasses, $5 from a gas station, so you don't go blind from the sun. 
A hefty garbage bag, $1, for when it rains--it's for my camera gear of course. 
A  handi wipe, free from gas station, for when you need a handi wipe.
Sunscreen, $1.59, to screen the sun. 
A band-aid, 5¢ for closing open gashes in skin.
Water treatment tabs, $15, for treating rotten water, most standing water is rot-gut bad in the Catalina mountains, especially after a couple of months with no rain. 
A Garmin etrex summit HC, $200 for pinpointing your location and relaying the information to the rescue chopper.
A Camelbak Blowfish 3 litre hiking backpack, $89, so I can store all my junk and carry my water on my back instead of swinging an 8lb jug of water in hand.  
Switch blade, free, I found it on a hike.  You just never know what might happen.  I've heard of a guy who had to hack his own leg off after a tree fell on him in the wilderness, I hope that won't happen to me.
Tripod, $17, for those long exposure shots.  Purchased from un-named big-box discount store, you know the one, with junk cars, oil slicks and hillbillies all over the parking lot.
Now at the bottom, my Sony Ericsson W600i cell phone, $199 minus rebate, for chit-chatting with friends about nonsense and sending worthless pictures back and forth.  Also could be used to call in a chopper when you get too tired from hiking.
Panasonic FX100 pocket camera, $399, for all around picture taking, and you can use the LCD at night for locating the trail when you forget your flash-lite, like I did here.
Finally, the Black Diamond Syncro "walking staff," $89 a pair, for riling up snakes and fending off attacks by huge quadrupeds.

So let's add up the cost of olden day hiking: 59¢ ok, I could have just used tap water.
Now we'll add up the cost of modern day hiking: $1015.64 + tax.  Plus the $29 LED flash-lite.

I might add here, everything you see has been tested on many an occasion and performed great.

This completes yet another entry in-----the Idle chat room!!