Sounds questionable. Assuming it refreshes the look, it may ne good for a quick polish before a sale. If it were the roof of the house I planned on staying in for a while, I would install new roofing.
Edit:
This is just a coating sprayed over top, no granular replacement. The classy version of tarps. If it works, I suspect it is better to install on a schedule to protect the shingles then to spray on a roof that already hurting.
Roofing has become a whore's market.
We were due for a new roof after 20 years. I did a part patch overlay to get another year. The previous roof was done around 2005 and cost about $4K, all legit. IIRC ~ 1800 SF.
The 20 24 replacement started out with a quote of $23,000 from a full of themselves wheeler dealer.
Then came a flurry of cash only con artists in the eight to twelve K range wanting $5K cash down and they might come back but if one of their workers falls and breaks his back you lose your house.
I finally got the job done by a legit contractor with WSIB coverage and working at heights training, for about $7,000. Done in a day.
Since my old shingles were three tab I could have saved a couple of grand by letting a different contractor just put on a second layer. The new roof has architectural shingles and I don't think that's an option going forward.
The spray rejuvenator seems to be similar in concept to the driveway coating stuff. If you like the colour it might make you feel good but does it actually pay for itself. I mentally prepare for a new driveway every 20 years. If I coat it every five years at $200 a shot my $4000 repave ends up costing $5000, 25% more. I don't think I'd get 25% longer life. And the stuff is IMO, slippery.
Does the roof rejuvenator make the roof slippery? I go up there to clean the eaves and even the modest slope can be a challenge.
As the roof is being hosed down with the stuff the excess ends up in the sewer (leading to Lake Ontario) or on your lawn. What's it do to those?