If a contractor strictly seals where the animals are ALREADY getting in and out, you are paying for an incomplete job. It is imperative to strengthen weak areas, or else squirrels will return and cause new damage in the future.
(Once you have had a squirrel get into your structure, other squirrels can smell the odor and will exploit the structure's weak areas. Even 20 years into a squirrel issue, odor will continue to give you a repeat problem.)
We run traps every day until we stop making catches. (See FAQ to understand how traps are checked daily.) At that point, if we feel that we have caught all the squirrels, we seal the opening and the job is done! If we are not sure we’ve caught everything we “mark” the hole by stapling newspaper over the opening for one day. If the newspaper is pushed (has been moved) at the end of that 24-hour period, we know we have another squirrel to catch. If the paper hasn't been moved, we know it’s safe to finish the job, at which point proper repairs are made.