I am wondering if magus always have to have a Sanctum close by, or next to, their lab. Or can/do magus have labs that are just labs that they build in convenient places, found a aura or a place they want to be left alone in?
If there is a solo lab somewhere I would assume there would be a bed in it for the magus to use when there over longer periods.
Also would having a very reclusive/secret lab, with or without a sanctum, not be a very hard thing to maintain. Just thinking the magus needs to eat and drink. And over a season that would take a big amount of items or much time spent going back and forth. Making it very likely to be discovered, if someone wanted to.
Also I am wondering what stats or things do you find important to keep track of when it comes to your lab?
Are you using the optional rules in Covenants? That has many ideas for having your living quarters with your lab, or having them apart.
Keeping a lab secret - well, you can try hiding it with magic, making a fake lab that looks like a real one, or you could put it on a ship and sail out in search of auras on deserted islands.
Agreed with Covenants and Leap of Homecoming solutions above. The only real issue I can see in a remote lab is that it may be outside the Aegis of the Hearth umbrella, and that can be pretty dangerous.
I was not really looking for a solution, as much as I was looking for the answer to the question if players are having isolated labs and if they have sanctums attached or not.
And what stats and things people keep track of regarding there labs.
Most games I've played in, people have kept their living quarters and labs separate. Some people do like to have the two in adjoining rooms and put a sanctum marker over the door into one of them.
What statistics people keep track of really does depend on the rules you use. If you're using the rules from covenants you carefully track the size of the lab, it's upkeep cost and all the other statistics in those rules. Otherwise you just record the aura and if the familiar will be in the lab when you're working or not, and any experimentation risk factor. That's all you really need to track under the corebook rules.
Unless the site is extremely small, there's no reason a Magus can't build living quarters next to his lab. Whether this counts as a Sanctum, legally, is another matter and would probably vary from tribunal to tribunal.
It is really a matter of magus character's more than anything else. A paranoid Verditius with high Hubris might only feel confortable in his lab, amongst his precious creation, a wandering Criamon could have set up a few meditation places, with some crude lab as she is changing location with the season, etc.
Aside the magus character, it is a matter of resources and safety: except the most rudimentary lab, just the maintenance of lab could feed a whole peasants family for a year. And for the most advance lab, beside the monetary value there might only be a few craftsmen able to manufacture the very complexes equipment required in these advanced lab. Which leads to the second point: safety. Aegis is the best and first level of protection against any supernatural threats, having multiple labs means either forfeiting the protection of the Aegis or having to maintain several Aegis: does the mage have the virtus to do so ? Can he cast himself the Aegis or does he need some help ? If he needs help, the location of his secondary/tertiary lab will at least be known by somebody else... leading to the second aspect of protection: mundane protection and supply. If it is a secret lab, without TP available, it will be tricky to supply or go to the lab without being noticed, whether those noticing can be an issue is of secondary importance only: they can be a nuisance, spreading rumors of devil-worshipping, treasures (attracting all the thieves around), etc...
With time and resources, anything is possible with Ars and each of these difficulties can be overcame, but time is the most valuable currency for a mage, so he must have a very good reason to do so.
Finally, regarding owning several Sancti, I believe I read somewhere that it is not illegal as long as it is not abused to hinder other mages activities. Sanctum covers both the living quarters of the mage and his lab - it needs to be clearly indicated, so as if he has guests, they know where they can safely walked in and where they would be trespassing by entering a mage sanctum, thus forfeiting the protection of the Code. And a sanctum can range from a single, cramped room to a large building.
The two primary reasons to keep the two together are 1) convenience- if you live in a room attached to your lab you don't have far to walk to the lab, and 2) rules regarding sanctums- if you can only have once sanctum and you keep your lodgings and lab separate, which do you want legally protected? Now of course you can always set up secondary labs that don't have legal protection...
So once is more or less agreed that as a rule of thumb having the lab next to the living quarters and inside the covenant, the fun part is to think of the exceptions to the rule. Ezechiel pointed one with his wandering Criamon. Other examples can be found thinking that most covenants are placed inside or around magical auras, but some magi may prefer other auras. If your troupe have a Merinita among other House's magi, you can easily make the Merinita about setting his lab away if he finds a high Faerie aura. And going to the dark side, magi with Cthonic Magic may find Infernal auras tempting. Also magi planning to breach the code may find their ways moving away from their solades and setting the lab out in a hidden spot.