award travel first timer
Hi. Hope I found the right place for this post.
I've been accruing miles on US and UA for quite some time. I'm Silver on US with 80+K miles. Never used an award ticket for travel, mainly b/c I'm very flexible with my schedule and always seem to find a cheap ticket. Said differently, I've never found it worthwhile to use 20-25K miles in place of a $200-250 phl-sfo/phl-las type run.
Given the current situation at US (which is not the focus of my post) I'm contemplating lowering my "value threshold" for using miles instead of $. Since I've never flown on miles I have some newbie questions, and I hope this community can shed light on some things for me:
1) while booking award travel on-line "costs" less miles than over the phone, is there any benefit to booking over the phone?
2) can you use award miles on open jaws, and/or something like phl-mco(stop)-sfo(stop)-phl. if so, how many miles do those scenarios "cost"?
3) after booking award ticket, can the dates of travel be changed prior to either outbound or return leg (provided there's availability). if so, is this a common practice (e.g. for extending stays), and therefore a "perk" of award travel, or just a good way to get stuck? also, is there any "change fee" for this?
4) after booking award ticket, can the destination be changed? say i want to ski, book slc first, but later see the snow is bad, and want to change to den.
5) as Silver, does my listing for an upgrade to F work the same way as if I used $ instead of miles? is my priority diminished using miles instead of $?
6) since everything is so cheap out of PHL, can I use miles to book flights for my non-family non-PHL less-fortunate friends who have to pay US > $300-400 to fly?
7) this is unrelated and potentially embarrassing but: I usually call after booking online to get listed to 1st, but online I always see that "apply upgrades" button - which I never use. I would think they do the same thing, but abide by the motto "if it ain't broke..." Are they the same?
Thank you in advance for your responses.
-Frank