The new ridge vent should have the bug/snow/rain barrier integrated into the venting system. There are probably many other areas in the attic into which "bugs" could enter, but attics do not typically make the best habitats since the temperatures can be extreme and there is no "relatively nearby" source of water for them to survive. The "integrated mesh" is more for helping to prevent wind blown rain and snow from entering the attic space and settling on whatevr lies below.

Definitely before you do the roof, masonary work and any flashing around the chimney should be done prior to starting on the roofing.

Our recommendation would be to do the massonry work first and then roofing for a few different reasons.

1.This gives the masons freedom to step and walk on the roof without causing damage to the new shingles. 

2. You will want to make sure the new flashing that is intstalled around the chimney is installed correctly, accounting for any masonry changes and is not damaged due to installation.

3. Ultimately, that the new roof is not damaged and that the warranty does not get voided. 

It is always better to repair the chimney prior to any roofing work. This way the new roof doesn't get damaged. 

Each case is unique but in general, the chimney should be done first. Special attention should be paid to the roof flashings around the chimney.  If the flashings are behind the stone then make sure they extend far enough into the shingles so the new roof can be flashed properly. If the flashings are surface mounted and there is a counter flashing then the roofer should have no problem making the chimney base watertight   

You might want to look into AB2299 for the state of California. Add additional living area and raise the value 160k-400K to all R1 Properties. We build these for a living and are seeing a 2% return rate on your investment.

Direct added value to your home:

Finish out unfinished living areas

Upgrades to bathroom and kitchen

Add additional living area

All other items completed to home have negligible value added benifits in terms of Apprasial added value.

Same as others said, Remodeling magazine's Cost Vs. Value report is a great resource!

As a roofing contractor, of course I am going to suggest an upgrade to your roofing system. And that's not just a biased opinion either. Working with a lot of realtors in our area it has been proven that the roof can be as much as 40% of your curb appeal. Especially when the system incudes things like the right color drip edge on the rakes and eaves, and high profile ridge caps. Both of those items are relatively inexpensive and can make a very noticibale difference compared to homes that don't have them. Selecting the proper type of shingle of course also plays a huge role. About 95% of re-roofs these days use a standard architectural tpye compositions shingle but picking something from the designer line can realy make your home stand apart. Then again, other rof covering options besides ashphalt shingles can make an even greater impact. 

As a GAF Master Elite Copntractor, we are partial to their line of products and I have included a link below to their designer apshpalt series.

Good luck!

http://www.gaf.com/Roofing/Residential/Products/Shingles/Designer

I agree with Chris.  The Cost vs Value report is the "go to" guide and is impartial.  Personally, I like to focus on first impressions and curb appeal.  Exterior dressings like corwn mouldings and simple shrub pruning is a great low cost way to give the home a wow factor.

You might also contact a couple of local realtors to see what people in your area are looking for in the home they want to purchase.

Check out the 2018 Cost vs Value Report from Remodeling Magazine.

2018 Remodeling Cost vs Value Report

This will give you an idea of the average return on your investment in the region where you live.

The one factor it will not give you is number of intangibles you may receive from the project you're considering.

• Lifestyle enhancement
• Number of years living in your new space
• New opportunities the space now provides

Make sure those are also part of your equation before making a final decision on the impact a remodeling project may make on the "value" of your home.

I would recommend that you look at remodeling magazine. They do an annual study of cost versus value For mini interior and exterior home improvements.

1. to make sure all crawl space vents are close .

2. you can check all exterior doors and windows do not have air leak .

3. check attick insulation should be minimum 10'' or you can add more insulation .

4.  you can cover large exterior window's glass with clear 3mil plastic .

5. you may check your heater system , and air filter need to repace every month .