The 1st or 2 spurts are normally always pretty decently far, prob 1 time not long ago sitting back, n it hit my desk a good 50cm away, There is many variables which can improve it or make it an impressive ejaculation, ie , Abstaining from masturbating a few days, be well hydrated, and not have any vitamin or mineral deficiencies , especially Zinc, Mood, Arousal level , edging, cock pumps n rings...... haha so yeah a fair bit you can do. Although another time when i shot far was the 2nd session that day so yeah it depends, most likely a'lot on how horny you are.
The longest spurt I remember was when my girlfriend gave me my first hand job. It went higher than my head and amazed her. She had jerked several other cocks and had never seen anything like that.
It's all about fluid dynamics, static pressure and nozzle design, right? A 500 gallon per minute fire hose can either go 25 feet or 150 feet.... I think the longest distance I get is about three feet....from tip down to the floor....
I haven't really seen a change with age, and I'm now 63. It all depends upon how long it's been since my last orgasm (more than a week brings major cumshots), how turned on I am (by far the greatest is with m2m), how long I have been edging (during masturbation or with a partner), and how hydrated I've kept myself (I usually drink a lot of water all day long, but sometimes not much at all). So it generally ranges between 1 foot and 4 feet (though the odd time it's only a few inches). But, my God, those 4 foot shots, with great volume, feel so amazing!
The distance has defiantly gone down over the years but one of the first times I was with my sister in law I pulled out from missionary and it shot past her head and could hear the splat on her headboard.