Reading, et. al...
Dangerous Dan--If you're reading up BEFORE purchasing equipment and supplies to do a new activity, you are Doing It Right. Good on you!
The "standard textbook" on reloading is titled
The ABC's of Reloading. It is put out by Krause Publishing. They must be doing something right; they just brought out the 8th edition of The ABC's. Website:
www.krause.com
Get it @ yr local sptg gds sto, gun sho, or over the I'net @ Amazon or the like, or contact the publisher--they sell direct.
The ABC's covers all aspects of reloading, and goes from the basics to much further advanced. Belongs on every reloader's bookshelf, well thumbed, IMHO. Having read it, you will be in a much better position to decide what you (1) must have to start with, (2) want in addition to #1, and (3) can wait to get. Or, decide not to reload after all. In any case, you will be far better informed on the subject, and there is no downside to that.
You will need a reloading manual if you decide to proceed in reloading. My go-to manual is the Lyman's; they just came out with the 49th edition. There are several good manuals out there, plus each maker of powder and bullets has info on the web of course.
The manual is like a recipe book--how much powder, which bullet, etc. The ABC's is a how-to and why-and-why-not-to type of book. So that is the one you should start with.
One thing you should NOT do is to use recipes posted anonymously on the Web. Any yahoo can post anything they want, and then you and your Old Betsy get to be the test case. Not a healthy situation. The websites of the powder companies aren't anonymous--I'm not condemning them, BTW.
In answer to yr question abt. primers and powder, the shelf life is VERY long given decent storage conditions, i. e. fairly cool and dry. They should be kept in their original containers. Ten years is nothing, to components thus stored. Posters to this forum occasionally report of shooting up old surplus ammo from WW II with zero, or very few, misfires--that's about 65 years in storage.
Oh, and welcome to The Magnificent Obsession--Reloading!