Short version is Yes.
However, I've still got a Palm Vx (1999) that gets played with from time to time and the battery seems work fine.
The question is not how long the battery will last, it's more how long it will last with heavy usage and the length of holding a decent charge.
Lithium Ion batteries are not as bad as Nickel Metal Hydride's in losing a charge or developing a memory but they will lose something over time.
My Tungsten T is now well over 3 years old and is still in daily use by one of my kids with no sign of needing a replacement.
Your mileage may vary but my advise is to keep your device in the charging cradle at all times when not being used out and about and from personal experience you won't have a short term problem.
