LG WM1832CW front load washer bearings bad after 4 months

[FamilyForce6]

I'm now reading that the spider assembly should always be replaced when doing the bearings. However, when I replaced the bearings I didn't see any visible damage to the shaft of the spider assembly. 

Is it possible (likely) that the shaft is worn down and in turn caused the bearings to fail prematurely? 

Should the spider assembly ALWAYS be replaced, even when there is no visible damage? 

Finally, when removing the spider assembly bolts I read to put heat on them while removing them. Should the heat be applied directly to the bolt head or somewhere else? I found this comment from mehoss: "Heat the spider only where the bolt is in, not the bolt while holding tension on the ratchet - it will let loose in about 8 seconds." I'm unsure of where exactly "the bolt is in" vs bold head...

Thank you!

 

[sh2sh2]

Yes spider should always be replaced as well as bearings and seals, this is why most professional companies will only replaced everything at once to avoid repeat issues