We don't use an elaborate system, like Nialldubh does it, we level the PCs up whenever we think that the time is right. In a 2 PC group where I alternately GM and play we so far had around 14 adventures (some longer, some shorter). The PCs started at Level 1 and have just reached Level 7.
Seems like about 2 adventures per level up, one of them should be a major one. We didn't want the characters level to fast so that we can appreciate and evaluate the new abilities that come with each new level (although the first 4 adventures were rather short, it sucks to be so squishy).
Let me see, what did we have so far ...
1) 'The Vault of Thedipides' in Nemedia (Signs & Portents 47).
2) A short adventure vs. slavers in Ophir on the way to Messantia.
3) A pirate adventure, the PCs got captured and thus 'The Ark of Delight' (Signs & Portents 52) began; in Khemi.
4) A short adventure vs. a man-eating duo of witch-mother and half-demon son, also some undead; at the coast of Shem.
5) A pirate adventure, modified 'Ghost of the Deep' (Signs & portents 27)
6) 'Wine of the Gods' (Signs & Portents 69), spiced with a night at the Ruins of Dagoth Hill.
7) 'The Book of the Elephant' (Signs & Portents 58-60).
8) A road adventure via Zamboula (cannibals) to to Agraphur (big bar brawl), culminating in becoming pirates on the Vilhayet Sea and combat vs. the Turanian Navy and Lemurian Cultists.
9) An adventure in the southern Turanian desert, involving an oasis, abductions of maidens by winged demons, ruins with ghouls, more ruins with winged demons and the rescue of the abductees.
10) While on a ship coming from Iranistan, an adventure at the Zembabweian coast vs. an infamous Zingaran pirate crew.
11) After a long sea journey around the southern lands on a big Vendhyan deepwater trading ship (fight vs. black corsiars), an adventure in Kush vs. cultists and wild beasts to find a hidden treasure deep in the jungle.
12) Back in Messantia began an adventure focused on the noble bastard heritage of on of the PCs; in Zingara.
13) A 'Pirates of the Caribbean' and 'Monkey Island' -inspired adventure vs. a Ghost Ship (The Flying Shemite), its crew of Risen Dead and Deep Ones and its sorcerous half-man / half-octopus captain.
14) A bloody conflict among pirate leaders (the PCs among them), the capture of one PC by the Shemite Navy and his rescue by the other PC.
