I wanted to migrate from my older registrar to GoDaddy. Main reason because current registrar/hosting provider doesn't support .NET.

My old registrar gave me control over the domain and hosting account. So, basically I have everything I would need. ( I know theory only )

I applied for Transfer of domain, bought a hosting package from GoDaddy and uploaded new web site.

So, I am waiting for domain transfer and it tells me that I have to wait for 5-7 days for approval. Okay.

But today, my old registrar told/taunted me that I really didn't need to apply for transfer. What could possibly I have done differently? My domain expires on this 15th.

Now I don't know much about how all of this really works, but I am guessing he meant, "you should have waited for 15 days and let it expire after which you should buy the domain as it is expired".

Is it really so(I doubt) or

there are some other ways I could have got same result but without transferring domain? (like, changing DNS entries)

I have read like all of the documentation available on namecheap/GoDaddy/Whois about domain transfers. But maybe because I am new to this it is all confusing to me.

I would also like to know what to do with DNS settings after transfer succeeds. I want to kill the old website. So, what nameserver settings I need to change, new one or old one or both?

I have old host+old domain registrar + old working site on one hand, on the other hand, new site + pending domain transfer + new DNS settings.