Spiker:
Whatever saw you finally get, make sure it has a greaseable roller nose bar and if it comes with anti-kickback chain, loose that and get .404
chipper chain. The only difference between anti-kickback and regular
chipper is the projection on the raker's. Get a saw with enough power to run .404. The .380 has a substantially smaller tooth and won't sharpen nearly as many times as the .404.
When you get the saw, get a couple of chain files and a small mill file too. Learn the proper method for sharpening a chain and keep your files with you when you go cutting. I always keep my chains sharp. It's easy to file a chain once you learn the proper method. A good tip as to ascertain when a chain needs touched up is when the wood pitch starts to build up on the heel of the tooth. Also, get yourself a couple of disposable grease guns with needle tips for greasing the roller nose. Grease it before you start cutting and about every hour after that and when you are done. Use a good grade of bar oil, don't use old motor oil. You need a gear type oil with a good film thickness to lube the sliding chain along the bar. Again, I use 85-90 or 85-140 GL4-5 gear oil, but you can buy bar oil.
I have a bench mounted chain grinder that I had leftover from my tree business but I only use it as a last resort, like if I hit a nail and chip a tooth. When you grind a chain, you remove a lot of tooth. Filing is much better and the chains will last a long time. The chainsaw owner that takes his chains to the shop to be ground every time is just wasting money on chains. Your local shop loves that customer, they get to sell him loops on a regular basis.
Watch your drive sprocket too. The rule of thumb is for every 2 chains, replace the sprocket. Watch the wear on the drive plane of the sprocket. When it becomes excessive, replace it. If you use a good bar lubricant, the wear is minimal and a sprocket can last through more than 2 chains.
Every time you switch chains, take the bar off, clean the chain groove with something that will fit to the bottom of the groove like a plastic credit card. The re-install the bar, but flip it over so the top is now on the bottom. That allows the bar to wear evenly on both faces.
Keep the chain tension fairly tight. You want the chain to contact the bar all along it's bottom edge and when you pull the chain away from the edge, you want it to "snap" back. Experience will tell you how tight. A chain that is too loose will tend to track out of the bar groove and come off.