I got a 6500bg and made the mistake of using it straight out of the box, like ya could in the old days.
After three months with a couple of uses a week and a scoosh under a warm shower afterwards it was pretty ropey.
One of the bearings had seized.
So I opened it up and the lubrication protective grease etc was almost non existent.
Now I'm not a perfectionist, just an angling dood, so I slapped car grease all over the inside of both backplates and used clean 10/40 engine oil for the bearings/level wind.
Should be fine for the rest of the season now with just an occasional spot of oil.