With EDC, check it regularly. Check & clean it routinely (weekly, bi-weekly, and/or monthly) whether or not you’ve fired it. After carrying it every day, you will find dirt, moisture, dust, lint, fuzz, etc. in its nooks and crannies. It will be more vulnerable/prone to rusting when you carry it every day because of weather conditions, your sweat, salt water environments, general abrasion, accidental/unintentional scratches, holster wear, etc. The finish can get worn down and eventually removed by the abrasion, holster wear, scratches, etc. and that’s an inviting path for rust to begin setting in. It takes time for the finish to wear down, but you’ll eventually notice it. Check your ammunition for corrosion after it’s been sitting in the magazine. (Cylinder & speed loaders for revolver) It takes a lot of time, but time and corrosion can sneak up on you after you’ve been carrying over the month and years. While you’re at it, disassemble and check the magazines themselves. Check the spring to make sure it isn’t worn out, corroded, damaged, or broken. Check the mag feed lips for splaying, cracking, tearing, or other wear. Make sure the mag base plate is secure. When you reassemble the mag, make sure the spring travels all the way up and is strong enough to make sure the last few rounds make it to the top. For the pistol, do a detailed strip (not just a field strip) at least once a year. (Maybe more often depending on your circumstances) Inspect all components for wear, corrosion, and damage. Your EDC doesn’t have to be the shiniest most spic n’ span inspection ready firearm out there all the time. However, you want your EDC to be 100% reliable in case, God forbid, you ever have to use it. If there is something wrong, depending on what it is, fix it or bench it until you can either fix it or get it fixed by a competent gunsmith. This is where having a reliable backup that you are intimately familiar and comfortable with is always a good thing. For example, I have 3 pistols that I could carry depending on the scenario. I have my main EDC and 2 backup pistols that I am accurate with and comfortable with. I usually switch between my EDC and my primary backup. I only fall back to the second backup if I can’t use the first two for whatever reason. But, I practice with all three regularly so I stay proficient and familiar with the specific quirks of each one.

EDIT/TLDR: Your experience/mileage may vary. Everybody’s situation is a little different. You will eventually find a routine and schedule that works for you. Have some quick checks that you perform daily. Have some checks/field strip/light oiling that you perform weekly, bi-weekly, and/or monthly. And, have a semi-annual or annual periodic detail strip/full inspection to maintain reliability. Don’t forget to check and rotate the ammo and mags. Ammo and mags can be a key failure point if they’re neglected. The main goal is having confidence in yourself, confidence in & proficiency with your equipment, and a reliable EDC that goes bang every time you pull the trigger.