So you buy a nice two shelf bookcase but it’s wobbly and you know it won’t hold much. I’ve recently gotten one and my solution was to put L-brackets on it. After installing about 8 of these brackets at the cojoining parts of the shelving, it is now completely stable and ready for use.
Do not do any plumbing or electrical work yourself unless you are a plumber or an electrician respectively.
Consequences for mistakes can be extremely costly and/or deadly. If you rent, it’s your landlord’s responsibility to get that stuff handled. If you own, just pay the tradesmen to do it right.
I disagree. You probably shouldn’t rewire your house yourself but changing out an outlet/switch or installing a water softener are extremely easy tasks that would not be worth hiring a contractor for. There’s quite a lot you can safely do on your own as long as you educate yourself and triple check everything.