Last year, my wife and I finished out two-player (her PC and my GM/PC) "Hammer of Æs" Hyborian Age campaign.  We started the campaign back in 2012 using the Mongoose 3.5 Conan game.  Then in 2014, we switched it over to Barbarians of Lemuria.  Played that game off and on till October of 2025 - numerous sessions!

I have a house rule that a starting character is a Hero.  After 5 APs they are a Legendary Hero.  Then after 10 APs they are a Mythic Hero.  At 15 APs they are Epic Heroes.  That is as far as the advancement goes.  The characters can still keep going, just no more APs.  This really suited our campaign.  

We still have a couple of long running campaigns going at this time, one is our Jalizar campaign (using the Beasts and Barbarians setting), one is a Warhammer Fantasy campaign (but that one is being switched over to Shadowdark RPG) and a Witcher campaign too.

Currently, we are on a Shadowdark RPG kick and have been using that system for the last 6 months or so.  I also started Soloplay, currently using Shadowdark, but have a couple of campaigns planned out for BoL - one set in the Border Kingdoms of the Hyborin Age and another set in the Dread Sea Dominions from the Beasts and Barbarians setting.

Yes, BoL can be used for long campaigns.  

I have mentioned here (and elsewhere) before that the constant desire for PC advancement in players is a facet of D&D that has influenced the wider hobby. Simon's advice to be stingy with advancement points is something he put out there from the early days of BoL.

My players have always liked 'advancement' in the setting rather than on the character record sheet. In my Ancient Egyptian campaign the PCs growing influence and reputation in society was what advancement meant to them. In my Gamboa Station campaign the PCs reputation as reliable hires who got the job done whatever it took gained them power and influence in the hive of scum and villainy.

To be fair, PCs getting more and more powerful in a mechanical sense was dictated by the 'zero to hero' design of D&D, but players came to expect that in other systems. And for many roleplayers such advancement is a major part of their enjoyment of roleplaying - the glee of levelling up is a big part of the game for them. And if so, good luck to them! I'm glad they are having fun. But if that is a big draw for them, then I suspect they are never going to really enjoy BoL mechanics games, except for the occasional one-shot.

There are other ways to play and I personally don't enjoy 'zero to hero'. And that isn't a style most sword and sorcery tales emulate. I don't believe even a 17 year old Conan was a Level 1 character.

In the Ancient Egytian game I ran, over some 22 sessions, I handed out AP at significant developments in the game or in the PCs lives. This worked out at around 1 AP a session at first, as lots were happening to the PCs in the early sessions (becoming a troubleshooter for the Regent, becoming a sorcerer, cleaning up corruption in Thebes, becoming spies, etc.) Later on I became more stingy as the PCs became more movers and shakers in the world.

These days I mostly hand out around 1AP a session, but it sometimes varies. In our WW2 game I have been more generous as the main PC is learning a lot, very fast!