Originally Posted by
Iride01
Size your new chain to the old chain. If you have issue shifting it might just be slight tweaks of the adjustment screws, not the limit screws. However if the chain doesn't stay on cogs or rings. Or it skips on the cogs or rings, then you might need to replace them too.
For me, personally, I could not always rely on comparison to the old chain since worn chains might have stretch in them and can mislead you to break your chain too long. I have found more reliable success when you size the chain routed along your largest front chainring against your smallest back cog on the rear. Park Tools has awesome, in-depth yet clearly explained videos on YouTube to measure and size your chain. I'm sure your local bike shop won't mind taking a look at whether the teeth to your cassette or front chainrings are worn to see if the problem isn't just the chain.