I look at it 2 ways, send them to local shop's grinder when the the cutters need more than you can do with a bar clamp file guide, and or touch up in between with the file and guide. There are tools you can use in the field to quickly dress up a chain to get through, but I like a little more accuracy and most times I can afford myself just that.
I've always been able to do an accurate job on the touch up, set the guide carefully, count the strokes, note any cutters with particular problems, look over my chain etc. At some point you have to take the depth gauges down proportionally to the top of the cutter and for me that has always been a problem, so lately I just run a bunch of chains, start from new, touch up, gets rocked it goes to the shop, then hung up for future reference. I'll repeat with new until I have enough chains in use for my needs. I work with the one chain until it needs to go to the shop, and I can get several touch ups before that, all depends on cutting conditions, or if you hit some wire or metal etc.
I can sharpen the cutters to be like a new chain with my file guide, but I was never all that successful with the depth gauges, lucky a few times getting them just right and the chain I use, Stihl RS, will pull very nicely into the hardwood I am cutting. I have taken them down too far, mis matched, missed one, and on those it does not take much to get some chatter from taking them down too much, or just dust/fines from not enough.
On that note, the grinder, like the file guide needs to be accurate enough with firm adjustments, (not built in a flimsy manner) and depending on the wheels used, etc, you must be careful to not overheat the cutter as you sharpen it. There are some reasonably priced grinders out there, Oregon, Northern tool(knock-off's) etc. I opted for an old HOS Stihl, not modern by any means, but its well built and holds the adjustment, and can do depth gauges by changing the wheel. I have not mastered this yet, nor have I spent much time on it so far, so I still use the local shop. They know how to to sharpen chains and perform repairs on about any saw you bring to them, its been in business since '49 or so and was founded by my neighbors father. I thought he may have had a Silvey or commercial grade high production grinder, he does not and they do a lot of chains and have a reputation for good work that I have heard about 40 miles away. He uses an Oregon grinder, not sure of the model, might be a higher end one.
Another thing is to use lots of care around your work, I brush away dirt around the base of the cut, logs I need to block up, and avoid getting too close to the ground, it all adds up to a dull chain if you do not. Either hand filed or periodic sharpening on the grinder seems to work well for a moderate amount of seasonal cutting/clean up/land maintenance I do.