That particular item seems to me to be one that you put on and just sort of know how to use. If you're a wizard or elf, anyway. Maybe other classes would have to attempt a spellcheck before they'd feel the power of the ring. In any case, I think a lot of people do not find the ring, so it might not even be an issue (wasn't for my players).
Hamun Ry (Wiz 4)
Str 10 Agi 15 (+1) Sta 11 Per 11 Int 17 (+2) Luc 10 (Unholy House). Align: C. AC: 14. HP: 13. Melee +1, Ranged +2. Crit: d8, I. Save: Ref +5, Fort +3, Will +4.
Spells: 1: Choking Cloud, Comprehend Languages, Detect Magic (odd crystal growths), Magic Missile (mirror images), Runic Alphabet (Mortal) (ravenously hungry), Ventriloquism (rain of frogs)
2: Detect Invisible, Levitate (extremely difficult, d14), Mirror Image (20% chance to raise/lower luck by 1d3 points).
Equip: Ring of the Sand Djinn: +2 AC/saves, Invisibility for 1min/spellburn point, or unmake for great, unknown effect. Padded Armor, Longsword, Longbow, quiver w/20 steel-tipped arrows, 10 silver-tipped arrows, backpack, spellbook, quill and ink, sturdy parchment (10 sheets), 5 days rations, high leather boots, belt w/ belt pouch, gray robe, dark gray hooded cloak. Also carries 3 small mechanical toys: wind-up mouse, wooden puzzle cube, small jewelry box that plays a little tune.