User blog comment:KnocknickKnock/Lucy's Unused Power!!!!!!!/@comment-77.194.131.128-20140715085522/@comment-7418318-20140715105033

Not to mention that Lucy absolutely loves Fairy Tail. To leave the guild, even if it's only temporary, would probably break her heart. And it'd also mean she would have to give up her apartment, which is another something I can't imagine her doing voluntarily.