We have older kids so our situation is a bit different, but I know I always find it helpful to get as much input as possible when having a problem, so thought \I'd share anyway
We have always negotiated chores and revisited who does what on a fairly regular basis, as things are constantly changing in a family (outside jobs, children growing older, new babies arriving, new homes, etc). Not everyone is naturally observant and will step in to do what's needed, so clear expectations are hugely helpful!
One thing we implemented very early on and still do over 20 years later, is that my husband 'checks in' with me when he gets home from work or when I need to go out, am sick, or any other time I might need extra help. He always says, "What can I do?" It's an acknowledgement that he's not sure what I've already done and what still needs to be done, plus gives me a chance to prioritize what will help me the most.