たまに

たまに indicates infrequent occurrence, typically less often than ときどき.

FREQUENCY SCALE (HIGH → LOW):

• いつも: always (100%)
• よく: often (~70-80%)
• ときどき: sometimes (~40-60%)
• たまに: occasionally (~10-30%)
• めったに〜ない: rarely (~1-5%)
• 全然(ぜんぜん)〜ない: never (0%)

たまに vs たまには:

• たまに: neutral statement of infrequent occurrence
• たまには: emphatic, suggests 'for once' or 'for a change'

Example: たまには外(そと)で食(た)べよう (Let's eat out for a change)

COMMON PATTERNS:

• たまに〜する: to occasionally do ~
• たまに〜ことがある: sometimes ~ happens
• たまにしか〜ない: only rarely ~

ETYMOLOGY:
From 偶(たま) (chance, accident) + に (particle)