A) A Liberty is not nearly the same build quality as most any truck
B) Alignment is absolutely a maintenance item, IMHO.
Toe, caster, and camber can change with just normal driving. Bushings compress, bearings wear, and even solid metal parts can stretch/bend, still be well within their service life, and still impact alignment and drivability.
Example: The camber on my Jeep TJ is set by tightening an offset bolt. The compression of the bolt/nut is all that holds it. Even with NO offroad use, and only about 10K miles, the camber adjustment had "slipped" 2 degrees. Enough to induce the infamous "Death Wobble". Nothing was worn out at all, and simply setting the camber back makes it good until the NEXT time.
Before we traded my wife's Saturn, we had all the alignment records (now shredded). It's toe would change by almost a degree every year or so. All parts were absolutely tight, but it still managed to change. Quick alignment, and back in business.
Now, I agree we shouldn't NEED to do this so frequently.
Almost 10 years and over 100,000 miles on my Silverado- never had an alignment, no abnormal tire wear, tracks straight and true. For vehicles made in the last 15 years, this should be the rule, not the exception. Alignments are not a maintenance item. Without excessive wear (which calls for part replacement) or damage, you should not need regular alignments.
A division of Chrysler. Nuff said.
I believe there are some shops that offer lifetime alignments for one flat fee up front... (looks like Firestone has this Offer: Lifetime Alignment | Firestone Complete Auto Care )
that said, some dealers (toyota does, not sure about Chrysler/Jeep), offer free alignment checks.
Just be sure you go to someone you trust, otherwise, they will milk that alignment for a bunch of other work that may or may not need done.