A Gratuity for Window Installers?

[vonsworld]

I am having 10 windows and a door replaced in my home in mid December when it could be bad weather. The work is going to take two installers three days.

If all goes well I'd like to give them a tip when the work is finished, what would you recommend?

Thanks

 

[Wayners]

If I was fitting then maybe a grand tip would be nice.
Ha.
Most I ever got was £50. Few bottles of wine over the years and chocolates.
Being given extra wasn't a common thing though, most dragged heals when it was time to pay

 

[Mottie]

If all goes well I'd like to give them a tip when the work is finished, what would you recommend?

Don’t stand up in a canoe.