You're right, if by "over time" you mean "aging" as the first step of a heat treatment process. From a quick search:

"Yes, some metals can soften over time, but it depends on the type of metal and how it's treated:

Precipitation-hardening alloys

• These alloys, which include aluminum, magnesium, titanium, and nickel, can soften when quenched and then harden over time. This process is often called "aging".
• Cooling rate
  The rate at which a metal is cooled after being heated can affect its final properties. Slower cooling can result in a softer, more ductile metal.
• Heat treatment
  Heat treating metals can alter their physical and chemical properties. For example, diode lasers can be used to soften hardened steel by exposing it to heat and then slowly cooling it.
• Metal fatigue
  When a metal is exposed to repeated stress or strain, it can weaken or break down over time.

The aging temperature for metal is usually between 700 and 900 degrees Fahrenheit, and depends on the type of metal and the amount of oxygen in the air."

But there's apparently no such thing as softening, whether of aluminum or any other metal, after the heat treatment aging process has finished. The closest metal gets to appearing to soften is localized hardening, which can result in concentrating stresses in adjacent areas of the metal that have not changed in hardness.

Anyone who has ever broken a paper clip by flexing it repeatedly has seen that happen. It looks as if the metal has softened, but it has actually hardened.

It can harden, you mean, as can any other metal, with resultant stress concentrations that can lead to failure.

But modern aluminum frame design (by "modern" I mean aluminum frames such as those designed by U.S. engineers in the 1970's and 1980's, including the original Klein and Cannondale designs) uses the properties of aluminum to ensure extremely long frame life.

On the off-chance that you haven't seen this report before, here are some results of fatigue testing of steel, titanium, aluminum, and carbon frames. (Short version: all the steel and titanium frames failed; two aluminum frames and one carbon frame survived. The testers pointed out that the failures of the steel and titanium frames resulted from insufficiently careful QC and/or the use of designs that left too small a margin of strength for the application.)

I've used mine for commuting, and for many years it was my only bike, so lots of road miles and the occasional foray on trails or gravel roads. No loaded touring, though.

If I didn't have so many other expensive hobbies (cycling, xc/alpine skiing, snowboarding, backpacking ...) I probably would have added that one. I didn't have the money choose to spend the required money/time on developing that hobby at the time. Though, with backpacking, I already had most of the gear, other than panniers. Oh well, you can't have all of the experiences in life.

You got a good bike for those uses. I got mine at the end of ‘98, so I got a great deal on it. Can’t remember the exact price, but I know it was under $800. I was lucky to find one because the ‘99 model had switched to brifters, which I didn’t want.

Worry about something important ! Like Russia nuking' the whole world ! !

Correction: if you sense that your metal frame has gotten soft, that's because it has cracked somewhere and is likely to fail very soon.

A metal's Modulus of Elasticity (stiffness) doesn't change with age.

That's what the blue pills are for.

Seek immediate medical attention for a ride lasting longer than 4 hours?

Whoa ! That would include a lot of stopping for me ........

I pull the seat post and drop 2 tabs of acid, then it thinks it can fly....

Are we building fall out bunkers and having kids crouch under desks again?... Not going to happen. Much more likely that Putin deploys a tactical nuke, but even that is highly unlikely. He's a soulless despot, but he isn't stupid or crazy.

In the spring of '95, my T700 was $800 (Narragansett Bikes - they're still around, though in a new location, and haven't dealt in Cannondales in probably 15 years or more). It had (still has - lives in my basement as my back-up bike) bar-end shifters, as you note. Originally, the front shifter was set up friction, and the rear was index. Eventually, I just went friction for both, especially when I switched from the original 7sp cassette (with spacer) to an 8sp cassette. It would have been funny to watch me try to install the first 8sp cassette, since I wasn't aware of the spacer on the hub body (hey, I'm not a bike mechanic, I only ever worked on my own bikes). Eventually my LBS pointed out the spacer (and kindly didn't laugh at me). I'm not sure why the bike had a 7sp cassette on a hub body that accommodated an 8sp. I didn't miss the extra gear, I only went to the 8sp when the 7sp became more difficult to find and when the 8sp was the practically same price as the 7sp anyway...

As I recall, brifters were not yet offered in '95 - I think that the R, ummm, R300? R400? still had downtube shifters, though indexed - which seemed to me to be odd and newfangled at the time.

we actually have a small sorta / kinda ‘bomb shelter’ in the basement of our house (built in early 50’s)

small room inside the basement with reinforced concrete ceiling (and reinforced block walls etc)

also had a fan and separate water supply, drain etc at one point (most of it now dismantled)

just recently saw a nice looking 1994 T700 listed on eBay

By the mid-90's, their mid-level and up road bikes all had integrated shifters, anything with Shimano 105 and better. RSX and RX100 took a while to get integrated shifters added to the groupset. Both got the upgrade sometime in the mid-90's though it wouldn't surprise me if it was after 95'. A related note, the first year any Cannondale road bike saw the new STI integrated shifters was some time in 1990 when Shimano debuted it in the Dura Ace groupset.

Touring bikes always seem to be the last to receive any newfangled technology, opting to stick with simpler tried and true tech. This is probably because the touring crowd is leery of anything too complicated that might break easily and/or can't be fixed easily in the middle of nowhere or in a third world country. Most of Cannondale's touring bikes kept downtube/bar end shifters until the end of the 90's.

I have a 1990 ST600, in fantastic condition I might add, that came new with 27-in. rims. Road bikes had all moved to the 700c standard at this point but because it was a touring bike, Cannondale was sticking with the old standard. I believe it even states in the original catalog that they went with 27-in wheels because replacement tires and rims could be found more readily in small towns. Probably true in 1990 but it sure doesn't help me now, which is why I converted it to 700c.

Thanks everyone. Some very good suggestions. Also some very frank ones, and funny ones

I dumped the suspensions fork recently. Much better without it. My tires could indeed do with an upgrade, and certainly the wheelset.

Indeed I think I'm going to concentrate on getting a good wheelset... and find a better excuse to get a second bike

Too true

Period. The end. Finito. And that’s a fact, Jack.

Beat me to it. Right there. It also doesn't change with increasing hardness and strength within the same family of materials, such as soft grade zip steel and hard spring steel, the elasticity is the same below the yield point, but the yield strength to plastically deform it is greatly increased with strength.

Regarding age... it's not underwear elastic.