1) broadly similar. A ‘linesman’ as the role is known is equally at home putting new wires up as taking down old and replacing with new.
2) renewal is easier in some ways, harder in others. Easier, because for typical renewals, which are campaign replacement of components, you don’t need to worry about structures. For the bigger jobs there will be elements of this (see GEML). However it’s harder in that you have stuff to remove first, have to design interfaces between old and new kit for each stage as you go along, and, most importantly, have to arrange isolations etc to do anything.
An aside: there is benefit in keeping some of the guys who put the stuff up on as maintenance. This happened in Scotland.