It best practice to change the sprockets at the same time you change the chain, less then say 2k ok but after 17k no brainer. If you don't it will reduce the chain life considerably, depending how bad they're drastically. It's your money.
I quality chain, properly maintained, ridden as many do, weekends, holiday in the dry should easily last 25k, many don't why......................
They're over and incorrectly adjusted, use aerosol lub that turns to a sticky paste. Yes the stuff sticks, yes it lubs but it's also a magnet for grit, and grit added to paste turns into grinding paste. They're dry lubs, these are silicon mixes, some are good others crap, for good ones, they're expensive, need applying every few hundred miles, they're better than sticky non fling aerosols, but need applying more often and for good one's bloody expensive. If expense is not an issue and you like a spotless bike, ride only high days, holidays in the dry, these are the way to go.
If your more like many of us, the best thing is plain old engine oil, yes it's not as convenient, needs to be done every 500 miles or so more if its wet, but it's better. As the grit is washed off, cheaper, you've already used the oil
Better still fit a Scottoiler (SO) and use the old engine oil. Many are put off by SO's, as nearly all are fitted and set up very badly by stealers or owners, which means they over oil, flood or don't oil.
I've lost count of the number of units I've fitted, to every type of bike, a good few to dispatch bikes that cover huge mileages, 30k plus yearly. I've had bikes in fitted new chain/spockets and a SO, they were still on the same chain at 45k, these bikes are ridden in all weathers, Busa's with 30k, one had 38k on the chain, same for R1's, GSX-R's, ZX's etc, all in excess of 25k. Chains with correctly fitted/adjusted SO will not need adjusting in 1000's of miles. My XJR hasn't needed adjusting since I fitted the SO to what was a 2k bike when I got it it's now done 6k, my ZX10 was the same fitted at 1,5k it's on 7k now adjusted at 5k.
The other reason is poorly fitted chains in the first place, either by the stealers or owners, it's not as easy as it looks. Poor quality tools and lack of experience and the link is just too tight, that's your chains life cut in half. Best way is endless but that involves major work, but is the best option.
Now if your happy with the convenience your sticky spray lub gives you, don't mind the mess in front sprocket housing/or frame/swingarm etc from over lub, or having to change it more often, you stick with it. It's your money.
If on the other hand, you're on a budget and want to adjust the chain much less, reuse old engine oil, either manually oil or fit a SO. If you don't trust yourself or your local BS to fit the SO drop me a line.