I split the job into smaller jobs and add together
So on bathroom suite job
1.First bit would be removal of bathroom suit,tiles,flooring,any walls ect
and taking away rubbish
2.Then first fit,running new pipework ,wastes,for new suite,wiring if doing, for new lights,extractor fan,ect
Also if any items have to be left working ie w/c,so will have to be removed,fitted every day and area left usable
3.Then making good/re building structure,walls ceiling,floors,sealing all as required
4.Then the tiling and grouting
5.Then bathroom suit instalation and last fix of fittings,lights,units ect
6. Then decorating if doing,snaging,removal of rubbish from site
The above sections I list on quotation,although give customer bottom line figure
The customer can see what is involved also
I have got jobs by doing this even more expensive than others because customer can see what needs doing to do job and they realise the other cheaper quotes would not be able to do it all for the price they gave
This also helps to set stage payments with customer,say inbetween sections
Also any extras,bring up with customer during what ever stage,so they can see issue