Remember the following is just my opinion and some ideas based on the most common areas of disrepair I've seen while looking at homes to purchase, improve and sell.
Water intrusion is a huge issue across the board in home ownership. A couple of tubes of caulk can limit already exposed or damaged areas of your home and possible prevent it all together. Exposed windows and doors are common areas for water intrusion into your home. Your roof is the other. Deep cracks and especially holes in your siding or stucco is also a possiblilty.
You will need a caulking gun ($4-10), exterior caulk ($-7), Painters tape ($5) and old towel. You only need the painters tape if you don't trust yourself to keep your lines clean or if you want or need really straight lines. It takes a little more time, but clean up is easier and it always looks great.
Regarding the caulking gun purchase a 'drip proof' one if you can afford to spend a couple extra dollars. If money is tight especially with so many people out of work due to the virus, you certainly can purchase the least expensive just remember to disengage it when you stop so the caulk does not continue to leak out (that becomes very messy and frustrating). We use Alex Plus 40-60 year, Alex Fast Dry Latex plus Silicone 50 year or DAP Extra Stretch most often. I like these because they clean up more easily and to me are just less messy! The old towel is for you to wet and is to be used to clean your fingers as you go and any overage.
If you have never used caulk or a caulking gun before just You Tube it. Also cauld comes in colors. Most of it is white and clear but the tube tips will tell you what color. I will give you a couple of tips.
1- PLEASE use your finger to press in the caulk. First and most important is it helps push the caulk into the little spaces you might have missed as you caulked. It is okay to add a layer in an area you missed. There is no point is caulking if you are going to leave small holes because water can find its way into the smallest of spaces. I can't tell you how many times I look at or purchase homes where someone used huge amounts of caulk, did not push it into the space and it's just jetting out in ripples along a window sill or door virtually doing nothing.
2- caulk will shrink a little from wet to dry so take a look the next day and make sure you are completely sealed. It is totally OKAY to go over an area with more caulk to 'seal the deal' as long as you use your finger to smooth it out.
3- warning- caulking can be addicting! Once you seal an area and smooth it out it gives the door or window or ceiling a nice finished look. I love it! It actually makes me happy! But I guess I'm kind of a nerd that way. I love the details.
4- Lastly, whatever caulk you end up buying consider buying a PAINTABLE caulk. If you decide to paint later and you do not purchase a paintable caulk you will regret it. Paint does not stick to full silicone caulk unless otherwise stated, so please look carefully.
On a side note, for any of you painting the interiors of your homes while you are stuck inside them, a neat trick is if you use a Paintable CLEAR caulk along the point where your ceiling and wall meet, once dry you can use tape to create straight, concise lines that won't allow the paint to seap through as long as you make sure the tape is securely attached to the dry, clear caulk.
As for your roof, a silicone caulk is probably best. Make sure all vents or any other attached items (TV satellites, condensor units, sky lights) are sealed. It's ok to go a little heavy on the roof due to the constant exposure to the elements. Remember to push the caulk down so you don't inadvertantly create a space.
For cracks or holes in siding or stucco, you can use caulk or for stucco they have stucco repair kits or cement patch. Fixing siding or stucco is especially important if you created a hole such as in removing a fence that was attached directly to your home. Water can get into that hole and effect your studs or sill plate (the wood that makes the walls of your home). That in turn could cause a nice enviroment for pests like termites.
Until next time, Be Safe and stay healthy!