The Nuance Difference: "たいてい" vs "退院する"

In Japanese, both たいてい and 退院する are often translated to English but have distinct usages. たいてい (たいてい (taitei)) represents "usually, mostly" (Level: N5) and typically represents Adverb of frequency. Indicates something happens most of the time, but not necessarily always. Stronger than 時々 but weaker than いつも.. On the other hand, 退院する (たいいんする (taiin suru)) translates to "to leave the hospital, to be discharged from the hospital" (Level: N4) and is used for Indicates the action of leaving a hospital after recovering from an illness or treatment. Opposite of 入院する.. Mixing these up can sound unnatural to native Japanese speakers!