Please remember that there are a number of different thread lockers available and you definitely don't want to use red Loctite (which is the one not designed for removing) or similar on those servo arms.

Loctite comes in colors to designate the recommended use, i.e. blue is the next color down and is considered removeable, but I like green. It's the next step down and is considered a penatrating variety so you must make sure you don't use a lot of it, but that is true of all thread lockers.

The other piece of advice is to replace your stock servo arm screws with the socket head type for Allen wrenches, that makes removing the screw a much easier experience as opposed to messing up the head of a Phillips type screw. Also, if you choose to not replace the stock screws, be aware that a lot of those screws use a JIS (Japanese Industrial Standard) type slot, not a true Phillips so it's easier to strip those screws out using the wrong type screwdriver.

I like to replace all my servo arm screws, but I keep a set of JIS screwdrivers around as well...

For engine mounting, I prefer to use the nylon insert type locknuts as opposed to a thread locker.