<いつも、時々>
いつも、時々などの英語頻度表現は下記のようにざっくりととらえておくと便利です。
always = 100% (いつも)
usually, normally = 80% (通常は)
frequently = 70% (頻繁に)
often = 60% (まあ頻繁に)
sometimes = 40% (時々)
occasionally = 30%(たまに)
seldom, rarely = 20%(めったにない)
never = 0% (まったくない)
参考:Let's Go Student Book OXFORD UNIVERSITY PRESS
厳密に何%というよりも、使い方のニュアンスを覚えましょう!
I need to go to the bathroom frequently.
I usually go to bed at 11p.m.