That wouldn't be "too much time" around here! I wouldn't stress about that until it comes up (if it does).
As far as penalties for breaking the lease... it would be the remainder of the lease. So, if your rent is $1,000/mo and there are 3 months left, you'd owe a maximum of $3,000, but the owner/property manager has to mitigate their damages (try to rent the place out), and they don't have to try all that hard.
Whether they find another renter before your lease is actually up usually depends on whether they think they can collect the $3,000 from you without a lot of work. It's usually easier to just find a new tenant, but that's not always an option.
If they find somebody to rent the place 2 months after you break your lease, you'd owe them $2k. If they find somebody immediately, but they have to reduce the rent by $100/mo, then you'd owe them between $300 ($100/mo for the remaining 3 months of the lease) and $1,200 ($100/mo for the year lease of the new tenant). Where your bill falls on that scale depends on the judge or how well you negotiate your position. Landlords will usually shoot for the high end of the scale and settle for the low end.
Good luck!
Billy
