The initial Li should be replaced very soon as it has certain special properties, including a reduced max level of 40 compared to the usual 60, so you can't actually max it like regular LIs. Generally during your 50s and 60s you should replace your LI weapon (class item is usually less relevant in this phase) whenever a new stock LI has a higher dps rating than your current levelled LI (with DPS upgrades). During this phase I'd recommend to NOT fill all your LI slots with trash LIs, as the amount of IXP you get at lower levels is very small and each slotted LI will slow down levelling of your main LIs significantly, so I'd limit it to 1-2 trash LIs at this point. Later when you get to Isengard and Rohan it's much easier to get IXP so then you can easily fill all LI slots without any significant drawbacks.
Note if you can get second or first age items (esp. class items) it might be worth sticking with those a bit longer than usual (e.g. a 75 SA weapon is good enough to keep until 85).
Last edited by Grimdi; Jan 17 2014 at 07:09 AM.
Used to play: 85 Champ / Captain / Runekeeper / Guardian, Guild Master of everything but cooking.
Playing now: Hellcat / King Tiger / GW Panther / IS / KV-5 / M4 Sherman and more