Maintenance on Daystate Regal?

There is no maintenance like greasing O rings. If you are OCD you can send it to an airgunsmith every 3 years or so to have all of the O rings replaced. Eventually they will harden and start to leak. My philosophy is "if it ain't broke, don't fix it". A friend of mine just had his Daystate PH6 resealed for the first time after 15 years of service without
any leaks until now. The best maintenance you can do for your Regal is just keep any dirt out of the quick fill and Foster.
 
While the rifle is supposed to be serviced every three years, this is really preventative servicing to check everything out at ghe end of the warranty period. Unless there is a problem then the rifle should be good for 5 years and you would expect orings to last to about 7 after which its just a matter of time before a leak happens though i have seen guns last for decades!