How to 理解 “总是 通常 平时 经常 常常”的区别？

“总是”emphasises on recurring
“通常”emphasises universal.
“平时”means that in general......
"经常"and“常常”they mean the same, the latter is more colloquial.

Oh ... I never known about them as I think they are quite similar.

【总是】：means always, every time. e.g, "I always have some fruits before dinner - 我饭前总是吃一点水果"
【通常】：means most time,normally, general case. e.g, "I normally have some fruits before dinner, but on Sunday night, just water - 我饭前通常会吃一点水果“ - it means there maybe some irregular exceptions，通常之外，也可能有exceptions，但这个exceptions不是正常有规律的exceptions
【平时】：means daily routine, general case, and with possible regular exceptions (compared with 通常) e.g. "我平时饭前会吃一点水果，但是周末的时候饭前只喝水"
【经常】【常常】：both means often, based on a regular routine，我经常去河边散步，我常常去河边散步 (not daily routine, but often happen)

总是、经常、常常all express frequency, they are almost the same, but 总是is more frequent. 通常 means general, in most occassions, it always orrcus when you choose something, for example 我通常会用这个牙膏；通常情况下，我会…… 平时means at ordaniry times, more emphasis on doing sth, for example 我平时喜欢看书、画画、看电影^