I posted this in a thread that got closed; I was curious just how much time it would take someone to do this so I started to do some napkin math.
The original poster assumed 5 seconds per gather and approximately 25 experience per herb. So going off that assumption:
Seeing as he started all the way back in September of 2012 (I'm going to make an assumption that this was on the day MoP was released, that could be wrong):
Amount of experience from level 1 to 90 (As taken from the XP chart available here:
http://www.wowwiki.com/Formulas:XP_To_Level; This appears to be off as it hasn't been updated for 5.3, I'll see if I can get a more accurate number later): 149,375,400 XP
149,375,400 XP / 25 XP per gather = 5,975,016 gathers to reach max level
5,975,016 gathers x 5 seconds per gather = 29,875,080 seconds of gathering to reach max level
September 25th 2012 to June 4th 2014 = 617 days
617 days x 24 hours = 14808 hours
x 60 minutes = 888480 minutes
x 60 seconds = 53,308,800 seconds
/5 per gather time = 10,661,760 seconds
/ 60 seconds in a minute / 60 minutes in an hour / 24 hours in a day = approximately 124 days (rounded up)
Discounting September of 2012, there are a total of 21 months between his start date and today
21 x 4 weeks = 84 weeks x 2 = 168 weekend days
617 days - 168 weekend days = 449 work days
449 work days x 24 hours = 10776 hours in work days
449 work days x 16 (Work + sleep) hours = 7152 busy hours on work days
10776 - 7152 = 3624 non-busy hours on work days
3624 hours x 60 minutes x 60 seconds = 13,046,400 seconds
3624 hours / 24 hours in a day = 151 days
168 weekend days x 16 non-busy hours (Accounting 8 hours of sleep) = 2688 non-busy weekend hours
2688 non-busy weekend hours x 60 minutes x 60 seconds = 9,676,680 non-busy weekend seconds
13,046,400 seconds + 9,676,680 weekend seconds = 22,723,200 free seconds since September 2012
So we're short:
29,875,080 - 22,723,200 = 7,151,880 seconds
/ 60 seconds in a minute / 60 minutes in an hour / 24 hours in a day = approximately 83 days
Note that this is using the old experience numbers for 85-90 from pre-5.3. Those numbers were cut by about 33% since then. I'll add to this post if I find the new numbers. It also doesn't take into account the pet battle quests I heard he completed on different characters and turned in on his pandaren, which there are about 5 per day and have scaling XP based on level. This also assumes a consistent 8 hour work day every weekday, and a consistent 8 hours of sleep every day.
EDIT:: Found the accurate numbers for 5.3, and it's quite the difference. (
http://wowpedia.org/Experience_to_level)
95,883,400 XP to max level (post 5.3) / 25 XP per gather = 3,835,336 gathers
3,835,336 gathers x 5 seconds per gather = 19,176,680 seconds
Now we're ahead, leaving:
22,723,200 seconds of free time - 19,176,680 seconds to max level = 3,546,520 seconds
/ 60 seconds in a minute / 60 minutes in an hour / 24 hours = Approximately 42 days of free time left over. (Rounded up)