This is a problem which affects the whole industry, some of which is our own fault, some of which is our customers fault.
I think I read somewhere that the industry as a whole suffers from at least a 70% staff turnover rate!
We have had 5 members of staff leave over the last 22yrs, so our staff turnover is very, very low, but then we offer them high rates of pay and a proper career path, with internal promotion, good terms and conditions, private medical care & pension, this of course means our prices are amongst the highest, but we do not have any problems with keeping our staff, this means our customers are happy and they always get the same staff on their site.