Here are some tips that may solve your problem and worth trying before you call in a professional...
1. In the case of mice... Points of entry are critical and must be sealed effectively to solve a problem long term. Look for holes any larger than a dime or cracks over 1/4 inch wide. Seal with a good heavy steel wool or copper mesh.
2. Multi Colored Asian Lady Beetles are, from time to time, a problem along the North Shore. They will arrive in swarms and on a bright sunny day, you can be kept busy for days vacuming up the beetles. Mix a tablespoon of Dawn Dishwashing liquid (Dawn seems to work best!!) in a quart of water and using a misting bottle or compressed sprayer, apply this liquid to the bugs on the siding .. They will die very qiuckly. This will allow you to enter the house and not bring in hoards of bugs with you. It does not do anything about them overwintering but it knocks them down for a minute.
3. Small sweet ants (Thief or Pharoah ants) will respond to sugar baits and mixing a teaspoon of boric acid or borax with some mint apple jelly ( an 8 ounce jar ) will give you enough bait for years.. Just put it on a business card or piece of thin cardboard and put where you are seeing the ants. They will eat up the bait and in a week or so be gone. Make sure you mark it "Ant Bait" and take the original label off as it will not make very good jelly after this..
NOTE... This does not work for Pavement Ants or Carpenter Ants as they are primarily protien feeders.
Black Flies .. Gotta Love em
While these tiny, 1/6th of an inch, black flies are found all over the US, they gather for a convention every Spring in Minnesota.
Generally black fly bites cause some itching and minor swelling from the first few bites of the season, following which an immunity develops, with subsequent reduced reactions. Nonetheless, even individuals who have lived all their lives in black fly country and are exposed every season, can have greater effects if they get an unusually high number of bites on their first exposure of the season.
Other than getting bit you can always try to avoid them - or keep them away!
Beware of sunset, right before a storm, and cloudy days.
Black flies are most active during daylight hours, and particularly on cloudy days. They are active in the early morning and evening right after sunset (peak time). Black flies are active right before a storm - but hide during rain or cold.
Get a bird feeder.
Much like our horseback rider friend, some birds (such as swallows) and other insects (dragonflies) find black flies to be a tasty meal. Another good reason to hang bird feeders in your yard.
Black flies have a sense of fashion.
Light shades such as orange, yellow and light green are less attractive to black flies than dark shades such as blue, purple or red. But black flies can't bite through clothing - so wear long pants, a long-sleeve shirt.
They also love perfume & babbling brooks.
Avoid wearing perfume, aftershave, or perfumed personal products when you're outside - they are drawn to the scent. And, unlike mosquitoes, which breed in standing water, black flies breed in running water.
Black Flies are lazy.
Or maybe they're just slow. Whatever the case, they can't keep up with you if you're walking fast. But if you stop - watch out!
Insect repellents work to keep them away.
You can always use any product that includes DEET. The 3M product Ultrathon is very effective. Whatever you use, make sure you put it on your neck, ears, face, wrists and hands.
I am experimenting with a mixture of Lavender and citronella oils mixed and applied on clothing .. There are a number of good repellants out there but just make sure you have something on hand when venturing out.
And if all else fails: You're safe in your house. Unlike mosquitoes, black flies won't go inside your house (or in a tent).
Good Luck !!!