"Надоесть" и "надо есть" sound different to me.Originally Posted by MasterAdmin
In "надоесть" only the last syllable is stressed, and the "а" in the first syllable is [schwa].
In "надо есть" there are two stressed syllables, and the stressed "а" in the first syllable is [a], not [schwa].
They can sound almost equal in a quick speech though.