Title 23 section 3104 was amended in 2017 to require the filing of a notice of claim to be updated every 18 months.  Here is the relevant part of the statute:

After June 30, 2018, any money owed pursuant to section 3101, 3102 or 3103 is not an obligation that burdens the parcel or runs with the land upon the transfer of any owner's interest unless a notice of claim is recorded in the county's registry of deeds prior to the transfer. A notice of claim filed in the registry of deeds expires 18 months from the date of recording unless extended prior to the expiration by recording of a notice of extension of the notice of claim. A recorded notice of claim may be extended for additional 18-month periods until the claim is paid. 

You can read the entire statute here: 

http://legislature.maine.gov/statutes/23/title23sec3104.html

So if you do not renew the claim, after 18 months it expires.  The intent was to not have stale claims still in the registry of deeds after the claim was paid off but no one went to the effort of notifying the Registry of Deeds that it had been paid.  But it also has the effect that if you forget to renew the filing, and then the person sells the land, you would not be able to recover the amount owed.  I'm not an attorney, but it seems to me there is some ambiguity here.  The statute says the claim expires if not renewed before it expires, but it doesn't seem to prohibit filing a new claim after the first one expires.  There would, of course, be a danger that the person could sell the land before you got a new claim filed, and then you would not be able to recover for the expired amount.