There will be some leaks with all masks at various times. That's a given.
How much of a problem those leaks might cause....depends on how big the leak is, how long it lasts and how much it might disturb sleep.
Most of the time the main problem is leaks cause wake ups and wake ups for any reason are bad news.
These machines can compensate for quite a bit of large leak which means therapy itself really isn't compromised all that much and the time it might be compromised is normally relatively short lived.
When I see a large leak flag the first thing I look at is how far above the large leak threshold did I go...then I ask how long was I up there and then I ask myself if I slept through the leak.
The further you go into large leak territory the iffier things get. Just a little bit into large leak territory isn't really that big of a deal in terms of therapy effectiveness.
