This is NOT an issue of "loading too much stuff" on your laptop. The explanation is simple: After a certain amount of time sleeping, your MBA enters into "hibernate" mode in which is will write the contents of your RAM to the SSD, and then power down more components.
Pros: Better battery life when in hibernate, because it cuts power to the RAM.
Cons: Takes a few seconds longer to wake up (since it is reading from the SSD instead of the RAM)
Here is how you can change/tweak how long it will take for hibernate to kick in. If you want it to take longer, you'll want a higher number.
1. Open Terminal.
2. Type (without the quotation marks) "pmset -g" and then press ENTER.
3. You will see the following readout:
Image
4. Locate the "standby" and "standbydelay" entries. "standby" should read "1", and "standbydelay" will be a larger number (I forget what the default is). The "standbydelay" is the
length of time, in SECONDS, after you put your MBA to sleep that it will wait before going into standby/hibernate mode. Also, make sure that "hibernatemode" is set to "3".
5. You'll want to change this to a larger number if you don't want your MBA to hibernate as quickly. I have mine set to 7200, which is 2 hours.
So, my MBA will not hibernate until it has been closed and sleeping for 2 hours. If I close the lid and open it back up within 2 hours, it works as "instant-on" (which is the behavior that you're looking for) -- after 2 hours of being asleep, it writes its RAM to the SSD and powers down, which makes it take a few extra seconds to wake up when I open the lid.
6. To change this number, input the following command into Terminal:
First, type (without the quotes) "sudo pmset -a standby 1" and press ENTER. Type in your password and press enter again.
Then, type (without the quotes) "sudo pmset -a standbydelay [the number of seconds you want your MBA to wait before going into hibernate]" and press ENTER.
If you wanted to set it to 2 hours, your command would be "sudo pmset -a standbydelay 7200" . Increase this number as necessary to get the behavior you are looking for.
I hope this helps!
James