As for maintenance, in order for any pistol, including a Glock, to be depended upon as a reliable self defense pistol, it will require regular maintenance. Anyone who says otherwise is being foolish with your life, since they are trying to get you to believe it does not need the same maintenance as do other pistols. Maintenance from purely shooters end is usually quite simple. it involves regular cleaning and lubrication of the firearm, at least with as much regularity as recommended by the manufacturer.
My personal preference is to field strip and clean, then lubricate, any pistol I have fired as soon after firing it as is practical. If you want to decide otherwise that is your choice. For example, if you want to listen to these words about firearms a maintenance as opposed to mine, go ahead:
I find that advice to be rather cavalier and less than responsible, but yet probably from a user who is trying to truly be helpful and who likes Glocks. While it could be that someone actually believes that such poor maintenance is all that is needed, I would ask - "Do you want to bet your life on it?". Why do I say that. Well I have some experience with Glock, and many other pistols. That experience would amount to about 15 to 18 years worth of experience firing them (just the Glock), and probably at least 10 years instructing others how to fire them (just the Glock, more for others) sadly I was to have become a Glock Armorer, but my class was scheduled on a bad day, 9/11/2001, and I opted to return to my office in NYC rather than stay in class. Still I have some experience in taking them apart and putting them back together, and much more experience in any problems they pose to a 'just shooter' type of person. They are good pistols - but they are not super pistols - they require regular maintenance to perform reliably.maintenance on a Glock??? no such thing... clean it every 1000 rounds and run a bore snake through it after every range session.... tear it apart real good for a cleaning every 10k rounds... it will out last you.
The best thing you can do with any firearm in general, is to take it out of the box new (or used) AFTER having read the instructions from the manufacturer if available, clean it, lube it, fire it, then repeat the cleaning and lubing bits. To clean it, you do not just run a bore snake through it. You disassemble it in a field stripping. You clean the barrel interior and exterior. You clean the frame, especially parts that have become fouled. You clean the slide, paying extra attention to under the extractor claw where buildup occurs quickly and where it can cause a problem with any semi-auto pistol with an extractor. You do this after each time you fire it, even if you only fired one shot. Follow the manufacturers instructions for making the weapon safe, for disassembly, for cleaning, for lubrication, for reassembly and so forth.
With Glock I also recommend at least a yearly check of the firing pin canal; this is based upon first hand experience - maybe even first experience of the problem that can occur. This is no BS, just fact: About 10 or 12 years ago (could have been longer), I complained to my primary firearms instructor on my job that the firing pin of my Glock 19 was staying in a protruded position out of the firing pin housing. I was concerned over a slam fire. No one seemed to think it was a big problem. They checked the gun. They pushed on the firing pin, it went back in but sluggishly. They striped it down all the way. When the firing pin was removed from its housing, it was seen that there was a buildup of brass shavings inside the housing. There was also a bit of gunk from oil and fouling. All in all it had accumulated in there and basically jammed the firing pin in a forward or strike position. It could be pushed back with a little force as I already said, and when a round was chambered it had gone back inside the housing, but it was an obvious problem. A little more brass, fouling, or lubricant could have caused a failure or an unwanted shot. They fixed it. First time that problem was seen, on my job anyhow; but you can bet it was seen again.
They contacted Glock. Glock recommended at least a yearly inspection and cleaning of the slide area that housed the firing pin. It was not the fault of ammo, not the fault of the gun, not the fault of the lubricant, not the fault of the shooter - it was the eventual buildup of debris as should have been expected by Glock, and was due to shooting an awful lot. For some reason they forgot to mention this to anyone on my job. Yes I shot a lot, maybe more than you will, but it is not a bad idea to check this every year. I certainly did not shoot anywhere near the 10,000 rounds as suggested above before needing to take it down completely for a really intense cleaning. When others, who had shot their issued Glock less than me, had their guns stripped and cleaned - guess what? The same problem was evident but not as bad. Crap builds up in the firing pin canal. It is, in my opinion, advisable to have it cleaned out by a knowledgeable armorer at least one a year. My job now does this as scheduled maintenance at least once per year.
Other than that, check with Glock (or any firearms manufacturer) now and again about recalls. In the years I have been assigned a Glock 19 there have been at least 5 magazine recalls. Glock willingly exchanged potential problem magazines with new ones of a slightly new design each time. The last time was years ago, but you need to stay atop of possible recalls on any part of any Glock, so check with Glock at least semi-annually on them.
All the best,