Are you in touch with your own mortality and all of its implications?
See, this is a tough question for me and I'm not sure I can answer it. I know that I will eventually die and I'm not sure if it will be sooner or later. I like to take one day at a time to accomplish my goals as is. I don't think I would have regrets if I did die tomorrow because I'll be dead and I wouldn't be able to regret it anyways...
Is it of benefit to be in touch with our mortality?
I think it's important to be in touch with the fact that we aren't immortals, it keeps us from doing stupid things. I've know many young people (in the past and I see it even now) that don't realize their mortality and does stupid things. My cousin died when he was 17 in a car accident. He was street racing and lost control of his car. The thing was, I don't think he ever thought he would die because he's gotten into a few pretty bad accidents (driving into a semi-truck and losing the top of his car) and yet he never learned from any of it and continued doing what he did. Oh maybe this is the view of a wimp!
What can a person do to be better in touch with their own mortality?
I don't know if there is a universal answer to this, we are all different, we are shaped differently depending on our experiences, thoughts and influences. I don't think one thing that will help one person get in touch with his/her mortality will be the same for another person. It's all something we have to learn/experience ourselves. I think there are some of us who refuse to accept death.
This could be the last day in your life or the life of someone close.
For me, that would suck, but I'll accept it since I don't believe that I will remember my life after I die so whether I regret it or not will not matter once I'm dead. I have big dreams and goals but I will only worry about it while I'm alive.
Will what you're doing now matter to anyone after you die, or even in 5 years?
I don't know if what I do would really matter to anyone now or in the future. I would like to know it does but unfortunately I haven't gained the power to influence the people around me yet. I accept things as they are and I would like to accomplish a lot and touch the lives of many people before I die, but if that doesn't happen - such is life (or I guess, death).
What can I do to make sure that I put things that will matter after I die as top priority?
Why should it matter what happens to the things that matter to me after I die? There's nothing more that I can do? I trust that the people I know and care about are capable enough to take care of themselves with or without me. In that sense, I have nothing to worry about. I don't have kids that depend on me and my family are all good, independent people. I would hate to leave pt but I know, in time, he'll get over my death...
You may not live to see milestones in the life of you, your family, and your friends which you look forward to and assume you will see. (Personal note: If I can ever bring myself to do it without crying the entire time, I would like to record videos of me talking to my kids which they can watch at various stages of life... graduation, marriage, having kids.

I may have to just write letters, as even this is difficult enough.)
Unfortunately, I don't find milestones that big a deal to me. It's just the next stage in life and I would be happy for those who reach it but I don't care if I witness it or not. Plus, like I said, if I'm dead, I wouldn't really have to worry about it. Since I'm not dead, I might as well try to enjoy life - although, realistically, I have a hard enough time with that, I can't worry about all the "what if's".
Others rely on you for specific tasks and information which are difficult to replace. (salary, pensions, savings, property ownership, business knowledge, fixing things, emotional support)
I don't think I really have anyone that relies on me that way. If so, I'm easily replaceable. Death of a close one is never easy to deal with but all the people in my life that I care about do have other important people in their life to help them in some way shape or form with my "death".
You might outlive everyone you know.
That would suck, since I hate being alone, but that just means that I have to be constantly making some connection with people or at least be wealthy enough to find a replacement for my feelings. Such as being rich enough to help a third world country develop so that I can touch some people's lives and also gain that sense of self worth myself. I don't know if this makes any sense...if I can replace the emotions I had for all the people I outlived, then I would at least be satified until I die.
If you live a long time, the world will be totally different from the one you know now, and you will be less capable of adapting to it by then.
I like to think I'm an adaptable person, plus, I think if the world did change (nomatter how long I lived), since I'm living in it, the change will not seem that big...it's not like I'm being plopped from one decade to another, I'm there to witness the change.
If you live a long time, you will likely be somewhat forgotten and be seen with less respect because Western culture values youth and those with potential rather than those nearing the end of their life.
But realistically, if things can change a lot in my lifetime, then that same assumption that youth is valued can change as well. Plus, I could always move to a culture/country that does value age and experiences. I'll just have to find someplace that will appreciate me for me and who enjoys listening to my many stories of: "I remember when I was your age, things were so different, we had...."
Thanks Javo for this interesting topic, I hope I answered your questions and that what I say makes sense. I'm quite tired and so my sentences could all be jibber jabber.