Well, the guys do have a good point about charging in a well ventilated and clear area (preferrably away from the house)... I would say at least initially until you gain confidence in the charger, etc.
If you are going to use a timer, I would say that it's better to set a personal alarm and be sure to go check the charger and cells. If it's close to done, then decide.
I guess the argument for a CellLog is solid for audible alarms on overcharge and discharge. If your battery does not have the correct connector for it, you can manually add it, or get someone to. It does save a lot of time - balancing and checking everything manually takes me 4 hours each time and after they hit a certain level, you really need to babysit them. I'm not married and have no kids or distractions during that time.
What you set the alarms at depends on the battery type, but we can all help with that.
As for fixing problems - I disagree with the thing I read once that cells are considered "balanced" when they are all at about 2% of each other. My cells all stay within .01v of each other. If your cells stay balanced, the battery will not be an issue.
Now here is where we may disagree, but I would never use over 80-something % of the rated Ah of my pack - and I have a Cycle Analyst that tracks and shows me that. I'm pretty sure that no cell has been under 3.25v, but I'd say less than 3.0v, the alarm should go off. Everything I read says 2.80v...
As for charging, from a personal experience, I had a cell at 4.2v and it did not blow up. I read that the magic number was 4.3v.... If a cell hits over 3.70v, I shut off the charger.
The reasons for both are complex, but the Cole's Notes (c) is that the Lithium batteries are designed to operate at pretty much a constant voltage for most of their life. At the end of their use, they start the drop in voltage and the rate at which they drop increases the lower the voltage. This is different than the batteries we are used to - which lose or gain voltage constantly over time.
So mine stay at about 3.36v for 80% of the battery's life. Then they take a while to hit 3.2, then about half that to hit 3.1 and half that to go to 3.0 - theoretically. I have not had the guts to go that far yet. I might when I have the CellLogs mounted like new's setup.
So this also applies when they charge. My pack usually gets a bulk charge to about 3.55v per cell, and then I let them sit for a bit. I hook my single cell charger (get Morph's suggested B&D charger if you want to go this far) and take them to 3.70v each. Once they sit they settle at 3.65v for each cell, after a day of no use, they are at 3.60v.
Charging time can be roughly calculated if you want. Take the Ah of the pack, figure out how many you used and divide that by the A charging rate of the charger. Example - I used 15Ah, my charger is 6A, I charge for close to 2.5 hours.
Manually, this is a tough thing with lots of intuition, hence why you stick with the charger that came with the bike and use CellLog alarms.