Reg - no, get an IP gauge like here
Regulator Accessories - Dive Gear Express
Check for IP creep and make sure its in range, if no creep, and your in range (~140psi for most regs) and it doesn't breeth like crap or free flow, then rest easy.
BCD - buy one of thes to clean up your inflator, then inflate it, stick it in a corner for a few hours, if its still inflated your fine
https://www.deepseasupply.com/index.php?product=1302
Computer - is the battery still good?
Then go diving
When someone says "omg your gonna die" cause you don't service your reg every year, just nod your head, smile, say "OK" and just go diving. Or "I won't dive with you!" just nod your head, smile, say "OK" and just go diving.
Some of my regs have gone 3+ years without service and still breath ok, but I serviced them anyway at that point. The amount you dive on them and abuse them will change their service life between services. Other regs I service more often, some less.