Debating on whether to share 2 of my GUC with a friend who is coming to Rome with me. I am already paid into D1 & they are in C+ and wondered what peoples opinions on sharing their certificates with traveling friends. I only had one trip left for the year to book (thanksgiving week) where I could possibly use them.

Anyone have similar issue/experience or words of wisdom. I worked hard for them and 99% sure won’t re-qualify again for diamond.

This sounds extremely personal and subjective. Only you can make this decision.

If the "friend" is a SO or potential SO, I would advise you to do it.

Otherwise, it depends.......

Before worrying too much about this, you might want to check whether upgrade space is available or likely to be released.

yeah I know just been struggling with what to do especially since I just found out you can�t use the certificate on miles & cash fares and the trip I�m looking at is somewhat pricey for Econ compared to using all miles

Do you mean miles and cash award tickets or pay with miles? They're very different.

Miles + cash option I was told you couldn�t use GUC with that option that it had to be a full cash purchased fare

Correct, you can't use them with Award or Miles + Cash tickets (which is essentially considered to be an Award ticket where you have partially purchased the miles). Most here don't consider Miles + Cash to be a good deal unless you don't have enough miles as you are paying for miles at the rate of 1.9 cents per mile (most people value miles at less than that). This is the cheaper than straight miles purchases (3.5 cents per mile), but miles purchases have more flexibility in the increments of miles that can be purchased than Miles + Cash awards.

And, for emphasis, miles + cash tickets book into award inventory (basically why GUCs cannot be used) and are based on the price in miles of an award ticket.

In contrast, pay with miles tickets book into regular inventory (like tickets paid entirely with money), but you decide how many miles to use to reduce the price of the ticket, at a rate of approximately one cent per mile with some rounding. They earn FF credit unless you pay for the entire fare with miles.

Sometimes pay with miles can be a better deal than an award ticket on the same flights and conversely sometimes cash and miles can be better than buying the same ticket for cash, although in principle dynamic award ticket pricing should mean that one shouldn't find big differences.