What's the difference between 度 and 回? [duplicate]

Question

Both are counters for occurrences. Would they be interchangeable in the following sentence?

パリ行きの電車は一日に二回出発します。

Answer 1

They have bit different.
First, they can sometimes be replaced. For example:

• 彼は一度(一回)だけ学校に来た
• 一度(一回)だけ成功した

But there is unable to replaced sentence:

• 第三回運動会
• (*)第三度運動会

In this cases, commonly used 回. Not used 度.

1. When used 第 or 全. (第一回, etc.) (Unable to use 度)
2. When counting decimals. (1.5回) (Unable to use 度)
3. When counting the number of actions.
4. When counting event in a row.
5. When you know number of held (happened).

In this case, commonly used 度.

1. When you do not know number of held (happened).
2. When counting event what is hard to calculate.

Answer 2

The followings with the sign "OK" are correct and used by Japanese nateives,

• OK: "何度もチャレンジする"
• OK: "何回もチャレンジする"
• OK: "３度目でやっと成功した"
• OK: "３回目でやっと成功した"
• OK: "試しに一度やってみたら？"
• OK: "試しに一回やってみたら？"
• OK: "早稲田には１回で合格したが、司法試験は３回（目）でやっと合格した。"
• OK: "早稲田には１度で合格したが、司法試験は３度（目）でやっと合格した。"
• OK: "第67回NHK紅白歌合戦"
• NG: "第67度NHK紅白歌合戦"

"今回はリハーサルです。" = "This time it is the rehearsal." "今回"　means "this time"

"次回はリハーサルです。" = "Next time it'll be the rehearsal." "次回" = "next time"

"今度はリハーサルです。" = "Next time it'll be the rehearsal." "今度" = "next time"

We never use "次度" at all.

Some people say that "回" has clear time window, but "度" donesn't have it.

I'm for it, but I feel that it is not the well-grounded explanation.

For me, the following is the best explanation for the difference between "度" and "回."

"一度で済ませた。" = "I've got done with them at one time."

= "I've got done with variou tasks at one time."

"一回で済ませた。" = "I've got done with them at one time."

= "I've got done with the task not at several times but at one time."

= "I've got done with the task on the first time."