I always take out the battery after a day of play, even if I'm playing the next day or weekend. The solenoid will drain the battery because even if the gun is off it is still electrically active with the battery in.
With regards to lube, you should be fine as long as you did a good job last time. It never hurts to pop out the bolt and take a look at everything to make sure there is a thin covering on moving/touching parts and dryfire it a few times if you have air.
"I tell my parents that as long as long as I am playing
paintball I won't be able to afford drugs.
They are starting to like paintball." - wangerinjaw