IMO if your poling all day every day 5 or 6 days a week you need more than one pole ,example:
main day to day pole(25 ft)to be able to reach awkward windows and 3 storey as well as run of the mill work
high level pole for solar panels,large domestic/commercial jobs,velux windows etc
emergency back up pole
extreme 25
extreme 47
SLX 22
buy the lightest,most rigid poles you can afford to cut down strain as poling all day does hammer the neck,shoulders and elbows.
the SLX poles are almost industry standard for work up to 30 ft these days.you cant beat the extremes though for an easier working day and for work over 30 ft they are superb.