Your instrument goes through a lot each week. Everyday playing can take its toll. Even though you may not be knowledgeable in woodwind repair, there are a few things you can do to help keep your instrument in good working order.
Daily
Be careful about how you assemble and disassemble your instrument. Sax students, don't wrap your hand around the octave key when putting on or removing the neck. Clarinet students, be sure to hold down a couple of keys on the upper joint so the bridge keys don't collide. Flute students, use the spaces of the instrument without keys to hold onto.
When you are finished playing, remove the reed from the mouthpiece and put it away! Think about it - your warm breath has condensed on the inside of the reed and mouthpiece. You're then just going to cap it and close it up inside your cozy case? Pop quiz: warm + wet + dark = ... what? You've got it. Mold. YUCK!! Not only is that totally gross, but it can also make you very sick. Just take a few seconds and put the reed away properly.
After you've taken off the reed, drop a swab through the instrument. After all, it's not good for water to sit on metal or wood. Sax students, you might also want to place a corner of your swab under the octave key to let it soak up any moisture that has collected there. (If you play bari sax, please regularly open the water key in the curve of the neck, and pull off the neck completely so you can drop a swab through it.) Clarinet students, use your swab to wipe away moisture that has collected in the tenon joints. Flute students, use your cleaning rod to get that swab all the way up into the head joint. Moisture can wreak havoc on woodwind instruments, so don't put them away wet.
Occasionally
Love on your instrument a little by giving it a good cleaning every now and then. Sit on the floor with your instrument, a clean paintbrush or key brush, a couple of Q-tips and tissues, cork grease, some scraps of paper, a polishing cloth, and a tiny screwdriver. As you're watching TV or listening to your stereo, brush the dust from under the keywork and tone holes. Use a dry Q-tip or a tissue to wipe away buildup wherever you might see it. Flute students, dip a Q-tip in some rubbing alcohol and use it to clean around and inside the lip plate. Clarinet students, use a paper towel or a tissue to remove the gunk that has started to build up on the tenons, then apply a fresh coat of cork grease to the corks. Flute and sax students, use a tissue to remove any oxidation that has started to build up on the tenons of your instrument. Clarinet and sax students, using cool water and mild dish soap, wash and dry your mouthpiece with a paper towel to remove calcium and gunk from the beak and chamber. Do not use hot water. (Clarinets, try not to get the cork wet.) Have a pad that keeps sticking? Slip a scrap of paper under the pad, gently hold down the key, and pull the paper out. Repeat until the sticky sound goes away. Go over all the metal of your instrument with a polishing cloth, fogging stubborn tarnished or cloudy areas with your breath first. Check for screws that are backing out and gently turn them back into place. (If there are repeat offenders that seem to back out every time you look at the instrument, try applying a drop of key oil to the screw before you turn it back into place.)
When to let a repairman handle it
Look over your instrument every week, checking for dents or cracks, bent keys, crooked rods, pads that aren't covering completely, or sticky pads that just don't want to go away. When you see problems like these, let a repairman take care of it. If you don't know what you're doing, you can inadvertently do more damage to the instrument by trying to fix it yourself.
Even if you are always extra careful, your instrument is going to require experienced hands to make adjustments from time to time - that's normal. But, if you take a little time to take care of the day-to-day maintenance, you can help your instrument last longer and require fewer trips to the repair shop. Plus, it's always fun to get complimented on the condition of your instrument from your repairman!