Most families should be traceable back to the start of Parish Registers (mid 16th early 17th centuries) some relatively easily others with more difficulty, which should take the researcher back to the late 15th century. Prior to that the difficulties start to arise as the records available thin out, relationships may be shown in wills. Clues to relationships arise in land records, tax rolls, court records etc. but there is often great difficulty in proving theories.
Even when making use of Heralds visitations often great leaps of faith are required to stretch a lineage back to the 11th century, if I remember correctly this has only been achieved by one family using the male line, though more have been able to using the female line as well.
I would therefore view all such pedigrees with suspicion.
Cheers
Guy
