I'm finally replacing the chain I put on my bike 30 years ago with a NOS Sedis chain of the same quality. The old one is stretched 1/4" over 55 links. Is that a lot? Did I get my money's worth out of the old one or what?

The new one is full of old packing grease. Should I just wipe it off and ride?

There is no harm in just putting the new chain on and trying it, but in all likelyhood, the rear cogs have worn down to the old chain's spread, meaning the new chain will slip and grind while you are riding. So, the rear freewheel/cassette will probably need a change too.

Your chain only lasted 30 years and you've gone and replaced it with one exactly the same? Some people never learn.

Seriously, if the bike's been in regular use you got your money out of that chain. However, the chainring(s) and sprocket(s) are likely to be showing a similar amount of wear and might not mesh well with your new chain. If so, they will need replacing too. The packing grease is fine to start with - Sheldon Brown recommends against removing it until it wears/washes away, but personally I always spray a little GT85 lube over the top of the grease and then squirt on a bit more every two weeks or so - wiping the chain clean and spraying it if I've been riding in the rain at the end of that ride, before putting the bike away. Everyone has different ideas about chain care though and you certainly seem to get a lot of years out of yours.

If by 55 links you mean 55 link pairs, i.e., 55 inches, 1/4" is not a lot. Less wear than the 1/16" in 12" (12 link pairs) that most of us use as the time-to-replace indicator. So your cogs and your chainrings should be fine. If, however, you mean 55 half-links (27.5"), then you probably have worn out at least some of the cogs and maybe the chainrings too. The reason I suspect you mean 55 inch-link pairs is that that would be a typical total length for a chain on a bike with a derailer.

I loved Sedis chains too. Even though you only got 30 years out of yours, I hope you will be less disappointed with your new one.

Just back from the first ride and it's smooth as silk! No problem at all with the Campy Super Record chainrings or the Suntour Perfect cogs, even the center one I use most by far.

It's always nice was it just works...