Quote Originally Posted by MasterAdmin
[можно] надоесть => from надоедать, sounds like "надо есть" (it's required to eat)
"Надоесть" и "надо есть" sound different to me.

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.