Springs off first, dome open, helper holding it. The two hinge springs carry the dome's weight. Every Big Green Egg method takes them off with the dome fully open before any band or hinge nut is loosened (BGE UK). No BGE document warns about it, but owners report a dome whipping open, and one was hit in the face when a band slipped (owner report). The dome and base are heavy ceramic (73 kg together): work with two people. A dealer can do it for you, and BGE UK offers paid servicing.
When: BGE Europe says check all bolts and nut caps about one month after assembly, then the hinge now and then. The 2026 and 2020 manuals draw a calendar marked "90" with spanners on every nut, read as about 90 days. BGE US: check the nuts, bolts and band hardware periodically. Wind, moving the EGG and use can let the dome slip (BGE UK).
This job only checks and snugs nuts. Moving a band or the dome is realign the dome.
The manuals' pictures, BGE Europe and BGE UK, with Ace (a BGE dealer) for which spanner fits which nut.