Our pediatrician said to offer each new food for 3 days before introducing a new one... Then she retired and we saw a different ped who wasn't concerned with it.

Did you do the three day rule? How long before you gave up on it? I think my current plan is to introduce 3- 4 foods over a day or two and stick with them for a few days and then add more in clumps. It makes the most sense in terms of grocery shopping at least...