Depends how you mean, items which degrade through wear and tear may do. Speaker bass units, turntable belts, cartridge stylus tip wear, etc, all have an impact on the sound. That said, I think older gear can have a very attractive sound to it.
With the exception of my DVD player, which I bought a couple of years ago for SACD duties and my cartridge, nothing is newer than 2001.
In fact, as of last night, the oldest item of kit suddenly became about 30 years old! A Sansui TU-317 analogue tuner and very much looking forward to hearing it I am!
I've just upgraded nearly my whole kit apart from CD Player with older equipment that was a steal in terms of sound per pounds and it's given me the sound I want/love (for now anyhow!!). Also agree that if you look after the kit, especially anything with moving parts such as a turntable, sound souldn't degrade too much. Then again, if modern recordings continue to deteriorate in terms of production/sound quality as reported in other posts on this site, you might find it difficult to tell if it is the mix or equipment.
Taking broken or faulty components out of the equation, does
the sound quality of HiFi equipment deteriorate over time?
Turntables need looking after more than other components. Electronics CAPACITOR do have life shelf and these would effect sound quality. As for speakers...depending on drivers materials. Paper cones and foam surrounding tend to go faster than other types although my uncle have a 20 years old pair and still looking like new.