During/over a period of time

[YoungFan]

Will you be home over the summer vacation?

Will you be home during the summer vacation?

Over a period of ten years he stole a million pounds from the company.

During a period of ten years he stole a million pounds from the company.

Wages have fallen by more than twenty percent over the past two months...

Wages have fallen by more than twenty percent during the past two months...

Plants need to be looked after and protected over bad weather

Plants need to be looked after and protected during bad weather

American business in Britain over the 1950s grew much faster than British business.

American business in Britain during the 1950s grew much faster than British business.

Over his lifetime he was relatively unknown

During his lifetime he was relatively unknown

Many strikes over the last few years have not ended successfully...

Many strikes during the last few years have not ended successfully...

These twin packed sentences are used with over and during respectively. I am wondering which of them are correct or make more sense than his counterpart? Or in which cases they are similar and can be used interchangeably. What's more, are there cases in which they both fit into but have different implications.

[Alan]

Generally, both are possible, with 'over' being the less formal of the two.