PII works from a date that you set when you take out the policy. If the jobs you want covered pre-date when you take out the policy, then you take out what is called retroactive cover (for more cost, obv) eg you take out a policy now, but want cover for all your work back to 2005, then you take out retroactive cover that will effectively start from 2005.
Every year that you continue paying premiums, you are covered from 2005, to the end of that policy year.
When you stop paying the premium, you are not covered. At all. For anything, anytime.
However, if you take out run-off cover, then all your jobs from the start date to the date of that policy is covered for up to 12 years after your death. Run-off cover is provided when you make a one-off payment, generally equivalent to 2 or 3 years premiums. There will be no more to pay thereafter.
What would not be covered would be any new work that you then undertook, which would have to be under a new policy.
PII only covers you up to the limit of that policy, including legal fees, which more often than not will be substantially greater than for the cost of the works being argued about. Once the costs go over that policy limit, you're on your own. Which is why most people these days work under the banner of an LLP or limited company.
