Some years back, I made sort of a half-assed commitment to work on all my bikes myself.
What makes this commitment half-assed is that there are a number of exceptions. For example, I'm more than willing to take delivery of bicycles or wheels that are already assembled, whereas if I were truly serious, I'd insist on receiving all the loose components in a burlap sack. Also, while working on your own bikes is ostensibly more labor intensive, I still find it easier both logistically and emotionally than dealing with the whole drop-off-and-pick-up process at a bike shop. Finally, I do reserve the right to say "Screw it," and hand the bicycle to a competent professional the moment I no longer feel like dealing.
So if I'm to be totally honest, my resolution is mostly personal preference masquerading as a moral philosophy, like those vegetarians who flaunt their moral superiority for not eating meat when in reality they just don't like it. (#notallvegetarians)
Nevertheless, half an ass is better than no ass at all, and I do feel that if you've been riding for awhile, it's important to make a sincere effort to service your own bicycles most of the time. Here's why.
It Helps Build Up Your Marketing Immunity
Sure, working on your own bikes saves you money, but it's more profound than that. Every few seasons the bicycle industry likes to present us with some kind of new "standard." Consider the bottom bracket shell, which over the years has grown bulbous and swollen, like a posterior that's received too many collagen injections.
The most oft-cited reason for this engorgement is "increased stiffness," and while the typical cyclist is about as likely to meaningfully flex any bottom bracket system as my two year-old is to straighten my U-lock with his bare hands, such claims can nevertheless be seductive—until your BB-whatever-number-they're-up-to-now starts creaking like a wicker papasan that's been left out in the rain.
If, however, you've been servicing your own bottom brackets for any length of time, when a new standard comes out, you can check out an exploded diagram before you commit and get a pretty good sense of whether or not the design makes any kind of real world sense or is more likely to be a monumental hassle.
Same goes for wheels, brakes, headsets, and every other component or interface that sees a lot of "innovation."
It Leads to Less Waste and More Sensible Choices
Once you've liberated yourself from the tyranny of marketing, you begin to approach your bicycle a lot more pragmatically. Not only do you eschew the latest gimmickry in favor of the functional and robust, but you also learn to make the most of what you already have, because getting your hands dirty gives you a much better sense of how long some of this stuff really lasts.
The price of components and wear items adds up quickly, and you should be using them for all they're worth.
Bike maintenance articles in glossy bike magazines would have you believe you've got to replace your chain every 2,000 miles, but for many of us this rule of thumb is patently absurd, and acquainting yourself intimately with your drivetrain and servicing it yourself will teach you how not to throw out that greasy baby with the grimy bathwater. There's a big difference between actual chain stretch, which can wear out your cassette, and a little surface rust, which may look scary but is entirely cosmetic.
Same goes for cables and housing. You may be replacing yours every season—or having them replaced for you when you bring your bike in for its regular tune-up. But do they really need to be replaced? Depending on your local conditions it's entirely possible they don't. Sure, sometimes your bike is asking for new cables and housing, but sometimes it just needs its barrel adjusters fondled a little bit.
Really, given the incredibly wide variety of ways and places in which bicycles are used, the idea of "service intervals" is mostly ludicrous, and there's really no substitute for making the bike bend over and cough.
And speaking of sensible choices and getting your hands dirty, becoming your own mechanic will probably convert you to black bar tape, because anything else is like wearing white pants to a food fight.
You'll Always Be Prepared
Ever need some work done on your bike before the big event only to find out everyone else does too and now the shop's too busy to get to it? Well, once you get in the habit of working on your own bike, this won't happen to you anymore, and you'll realize everyone else is the equivalent of those people you see in the news who drive 50 miles to Home Depot for water and batteries just as the blizzard's starting and then get stranded on the side of the highway for three days.
Then of course there's the matter of being prepared for mechanicals during your ride. You'll know how to fix them, plus you'll have a much better idea of what's worth carrying with you in the first place. After all, what good is that awkward 80-piece-cram-it-all-into-one-multitool if you don't know how to use it? A tool roll or saddlebag with some well-designed essentials and a headful of knowledge is a lot more useful than that flying orb from Phantasm.
It's Easier Than You Think
More than ever, today's bikes, with their integrated components and incredibly specific torque values scream, "Do not disassemble!" to the untrained eye. But don't be intimidated. All this stuff's still mostly just tubes and cartridge bearings held together with hex bolt fasteners. Sure, you might screw up, and you might even strip something, but that's the only way you'll ever learn.
Do you not try mountain biking because you might fall down? (You will.) Do you not ride cyclocross because you might look silly? (You do.) Do you not ride when it's cloudy because it might rain? (It won't if you don't ride but it will if you do.)
And sure, there's nothing wrong with crying mercy and taking it to the shop, but usually a little determination and a YouTube tutorial is generally all it takes.
Now get to work, and go easy on those pinch bolts.