Historically, underwriters consider 3 years.
Company records tend to purge over time. The 3 year practice may come from DMV records for auto insurance, which were typically 3 years for tix and accidents, 7 for DUI and other "major" infractions. Auto insurance kind of set the standard for regulators to expect similar claims history for legitimizing company actions. While it may now be more acceptable to regulators to consider a longer period (I was an underwriter for 16 years, but changed careers in 1999), it is probably only a consideration if there is a lot of claims history for all lines of insurance they write for the customer, or if background reports (CLUE reports
What Is a C.L.U.E Report and Its Impact on Your Insurance) show a propensity to file claims.
Also, if there are other risk factors such as poor upkeep, adjusters will note that on claims.
The practice of underwriting is one of balancing a lot of factors, and judgement plays a huge role. Claims are both good and bad in the insurers mind. Good because the expectation of claims justifies rates, bad because so many people mistakenly view insurance as an entitlement and file claims often instead of carefully maintaining property or driving. I can't tell you how many times I have heard the argument about paying more premiums than collected in claims with the aura of expecting it to balance. The flip to that is if an insurer has to pay hundreds of thousands, or millions on your behalf, should they be entitled to recover that? Of course not.
