"yourself" or "by yourself"

kenny1999"do it yourself.."
does it mean that you should do something on your own?

Yes.

Without help from anyone else.

The teacher showed everyone how to measure the amount of copper in the sample.

Then each student did it himself while the others watched.

But when you do something by yourself you do it

To do something by yourself pretty much always means that you are alone, the only one working on it.

To do something yourself can mean this same thing, or it can mean to do something without professional help. This is especially true with regard to home improvement projects or other tasks for which one would potentially hire a professional. For instance:

I built that porch mys

Thanks for your reply...

but ...sorry i don't quite understand....

How about "I spent the whole day myself.... " will it sound strange? or will it carry a different meaning?

kenny1999How about "I spent the whole day myself.. " will it sound strange?

Yes. Very strange. It doesn't mean anything. Don't say it.

Yes, that would sound strange. What you most likely mean is that you spent the day alone, and the way to say that is, "I spent the whole day by myself."

In American English, there is a saying "If you want something done right, do it yourself". This means, the only way to get something done to your expectation is not to let anyone to do it but you.

By one's self - basically means all alone.

I took out the old toilet and installed a new one; all myself self.( you did it with no help)

Sometimes, I like to spend a quiet afte

If "by one's self" means alone is "by ourselves / yourselves / themselves" possible? If we use a plural relfexive pronoun it's obvious there was more than one person, so how can it mean alone if the pronoun already points to the presence of at least two people. Would it mean that we / you / they did it without any external help?