I guess I ride too much. Sometime this spring IIRC I installed a new chain on my Roubiax. I've kept it lubed but was not really thinking of all the miles that I was putting on. While checking my chain a couple weeks ago I found that it was way past the stretch limit. Replaced it and my cassette. I also have had a bb creak and have changed my bb. Now in the small ring, middle cassette to small cogs the chain jumps on the chainring with even moderate pressure on the pedals, such as starting from a stop. In the big ring I've not noticed any problems. Is it a reasonable conclusion that I need a new small chainring?

Yes. Although there are many causes of chain skip that don't involve worn out teeth. But worn teeth certainly can cause skipping. Andy.

Andy, where else should I look?

I've just been through this. First I installed a new chain followed by a new cassette. This cleared my chain skipping. Had it not, next would have been to check for a bent derailleur followed by making certain the chain was the correct one for the cassette, that is, say, 10 speed chain for 10 speed cassette.

Pics! Pics! Pics!

BW- I would go through the system's entirety. Sometimes a new cassette doesn't sit exactly as the old one. So der range limit settings, cable tension/SIS adjustment, cable friction, cable condition (hidden fraying), casing condition (end cap punch through), bent ring teeth, chain not assembled correctly are starters.

Additionally since chain skip is the result of a number of possible issues it can be two different ones. I have seen worn freewheel/chain skip turn into new chain/old ring skip more then a few times.

But from your OP I'd say the old ring is the most likely cause. Andy.

+1. Pics of teeth on small chainring.

If it's the small ring and it has no offset, you can flip it.

Thanks all. it is the small ring, don't see any offset however the mounting holes are counterbored for the nuts (female threaded fastener). My LBS has one on the way for me at a reasonable cost. This is an all of a sudden problem after changing out the chain and cassette, No other changes.