Hourly or daily rate for tradesperson.?

[limetrees32]

I'm feeling very dense here but why do some charge hourly and some by a day rate ?
It's just cost me £ 2000 in labour for work to a very long fence .
Difficult access because overgrown jungle on neighbours side pushing fence over and some of it had to be hacked away ( brambles , ivy etc )

It was 2 days ,two people .

I never accept a quote with this. I want a fixed quote for the labour and a timeline.