Do the known and listed status perks exist equally among each individual tier, or is there a certain benefit to maintaining status? Say someone has been Platinum for a number of years and then bumps down to Gold, is there a gain/loss for/not continuing to maintain a status level? When talking to Customer Service I've heard vague responses about how older Platinum tiered members get cleared for upgrades before newer tiered members, and other Reps that say there is no difference. Problem being that no Rep will ever disclose reference sources when asked.

Status benefits exist equally among each individual tier. Length of time at a status level is not a factor in upgrade clearing.

There's a whole thread on upgrade priorities, length of time holding status has never been one of the criteria.

Understanding the Upgrade Priority

Welcome to FT!, cardcarryingunitedflyer

Longevity in an earned status tier has never been shown to have an impact on benefits.
UA does offer Lifetime status levels. After meeting a certain lifetime "butt in the seat" mileage threshold, you can earn a status level that you will never fall below even if your most recent annual activity is insufficient to earn that status level.

For instance, if you earn 1,000,000 actual flight miles on UA-operated flights, you earn Lifetime Premier Gold. Your status will never drop below Gold, even if your earnings for the past / present year are below the normal earning requirements.
So, longevity can help you retain status but even in that case, Lifetime Gold has no priority over regular Golds.
Lifetime status members are allowed to designate a companion to have the same status as the Lifetime member.

How are "lifetime miles" calculated for MileagePlus?

MileagePlus Million Mile (and Beyond) Flyer Benefits

Is it even worth it to go for million miler lifetime status?

Customer service agents aren�t trained in the details of the frequent flyer program. They know one exists and they know the hierarchy. They may know some of the benefits, but beyond that, one is usually wasting their time talking to them. They are trained mainly to sell and change reservations, not discuss details of the frequent flyer program.

If you look into upgrades at United.com, you�ll see no mention of previous status having anything to do with upgrade priorities. This is the same info they�d look at.

Apart from what has been mentioned (e.g. lifetime status) airlines only care how much you're flying right now - or in the very recent past.
They care naught what you did 5 or 10 years ago.

I will say that most GS agents are familiar with the program - specifically things like forcing upgrades at T-72 or T-24.

I would actually be surprised if, at some levels (probably not GA - but maybe on CS lines) there are some indicator of how "special" you might be as all 1k's/GS/etc are not created equal beyond the life-time status that Wine nicely summarized. Sure, there are urban legend stories like "Mr Pillows" and we all know Tom...... but I am sure that a GS that spends $250k a year is different than one who spends $50 or if your direct report is Tim Cook vs well anyone else.....

I stay a lot of nights at Courtyard a few years back and got to know some of the front desk staff and manager very well and they shared with me that I had reached a point in which I was flagged in the system as being a more special VIP guest than the average VIP....of course, didnt help with upgrades or any other perks.....but they did know my name and I knew theirs......

-m

I've had airport agents who know me particularly well either ask me privately (after a they encounter something new) or introduce a other customer to me with some of the "finer details".... The truth is I/we love in the system traveling from one cog and gear to the next; they're simply a gear (or perhaps even just a few teeth on a gear) in a giant machine... They know what they're required to know really well but all of the other little details, particularly those that don't pop up every day like YBM, may not be quickly at hand

This is not the case anymore.
Although I don't know officially it was a practice or at the discretion of the airport supervisors, there was one time I was upgraded as an 1K (in the PMUA era and before GS) on a HKG-ORD flight. when there were 60+ 1Ks on the list. I asked the 1K check-in agent why I was upgraded over other 1Ks, she told me I have been in the M+ program longer than other 1Ks.

She could just blew off with that response, but I thought I shared my experience here.
It is definitely not a practice now.

No one is special enough to matter to any airline, once you stop flying. It�s not loyalty, it�s a business relationship,

An inactive 10M flyer is spent and has no revenue opportunity. It�s not personal, it�s just business

Yeah - but that�s more because they actually implement the benefits.