I keep pressing the big button and closing one app to go to another. How do I switch between mail and Safari and Netflix and stuff without resorting to 'the button?'

try double-tapping the home button to change to the App Switcher. Swipe left/right to choose between apps, and tap once on the app you'd like to switch to.

(it's too bad a triple-tap doesn't switch to the previous app you had up)

Thanks. Do you see a lot of iPads with broken buttons, btw? you know, the kids.

Most common problems, roughly in order of occurrence:
- cracked screen
- liquid spill (killed/crashing/dock corroded)
- headphone jack problems
- digitizer problems
- home button not working (often following someone replacing the digi)

(take note, the top three are usually due to abuse)

less common, in no particular order:
- battery runtime
- LCD display
- speaker or mic
- wifi not connecting
- crashing / won't turn on (not liquid)
- poor audio quality

never seen problems with:
- any of the sensors (compass, accelerometer, etc)
- cellular not working
- backlight (surprisingly)
- IR face sensor
- multitouch (when digitizer is otherwise tracking fine)
- dock IO

Never see problems with the Dock IO, that one is surprising considering how much dust, sand, etc. can get in there.

the only issues I've seen are foreign objects (usually a splinter of wood etc laying flat deep inside, preventing full docking) or the obvious dark green or crusty white corrosion on the gold pins from water contact

Can you explain why my iPad, the model that was just prior to the iPad Air will only stream from the 2.4Ghz network and not the 5?

Although iPads have supported 802.11 a/b/g/n protocols since the very first model that was only in the 2.4GHz band. It wasn't until the 2013 iPad Air that dual channel (2.4 GHz and 5 GHz) and MIMO (multiple-input and multiple output) capability was added. That required a hardware change to implement.

One more stupid iPad question, please:
Are there any navigation arrows when you are editing text? Sometimes things like I want to add a period after say, a product name, and it keeps making the product name pink and won't let me squeeze in .

"It's so easy a three- year old can use it."
"Ok, go out and find me a three-year old."

I think the best you can do is press and hold in the vicinity of the item you want to edit. Your cursor will change to a magnifying glass (keep pressing and holding), which you can then slide around with your finger to the spot you want to edit.

By the way, if you type two spaces (space bar tapped twice) after a word, a period will automatically be placed at the end of what is now the sentence.