Depends on a lot of factors I got a fitted set (Driver, Woods, Irons) in July 2017 then upgraded my Driver & 3 wood in November 2019 because they weren’t right for me anymore. Got new irons last year because my old irons were game improvement irons and my new ones are more players irons (but not quite blades!).
I have Graphite for Driver, 3 wood and my 3 iron everything else is steel shafted but if the fitter gave me graphite everything I wouldn’t say no.
If you’re on a budget I’d recommend GolfClubs4Cash through in Edinburgh, can get some real good gear only a few seasons old and in pretty good nick!