I think you often use “always” in daily conversation. You can translate “always” into “itsumo”/「いつも」or “tsuneni”/「常に」in Japanese and Japanese people often say them in many situations. I will introduce when you can say them and the difference of meaning from similar words.
This word is not a particularly casual and formal expression and you can say it in many situations. If you stay in Japan and know “itsumon”/いつも as a meaning of “always”, there is no problem. Also I use it very often. I will introduce the examples.
He always complains about other people./彼はいつも他人の文句ばかり言っています。
I always take a walk to maintain my health in the morning./私はいつも健康維持の為に朝、散歩をします。
Japanese people also say “itsumo wa”/「いつもは」in some situations. It means that usually they do or don’t do something, but sometimes they don’t do or do it. I will introduce the examples because I know it’s hard for you to understand what I mean.
Usually I have dinner at around 19:00, but today I will have it at 20:00 because I will be late for my work./いつもは19時頃に夕食をとりますが、仕事で遅くなるので今日は20時に夕食をとります。
A:Why do you drink beer today although usually you don’t drink it ?/いつもはビールを飲まないのに、なんで今日は飲むの？
B:Also I want to drink beer because everyone is drinking it./みんな飲んでいるから、私も飲みたい。
This is a little formal expression, so normally I don’t say it to my family, but I often say it at the workplace. Of course you can say it in daily conversation although you may give people a stiff impression. I will introduce the example.
His motivation for his work is always high, so he is very nice./彼の仕事に対する意欲は常に高く、彼はとても素晴らしい。
Japanese people also say “tsuneni wa”/「常には」in some situations. They commonly use it when they deny something partly in negative sentences. I will introduce the example.
I can’t always watch his behavior./私は常には彼の行動を監視できない。
If you use “tsuneni wa”/「常には」in affirmative sentences, I think it’s unnatural. I have never heard the way of saying it.
You can translate “always” into “itsumo”/「いつも」or “tsuneni”/「常に」in Japanese. “tsuneni”/「常に」is a little formal. The meanings and the ways of using “itsumo wa”/「いつもは」or “tsuneni wa”/「常には」are different from “itsumo”/「いつも」or “tsuneni”/「常に」, so you should be careful about that.