You should not have any problem leaving your plants alone for 4 days.. I have never watered plants every 4 days....
Once or twice have watered every 5 days. but usually more like 7-10 days...

using 3 gallon+ size pots...

When I water I use at least 1 gallon of water and then let the plant sit in the run off.. The plant usually absorbs the run off within 1 hour...

just saturate the shit ouutta her.. and if you have to set her in a tray of watre..

iloveyou