Your smartphone and most applications are spying on you. Take action now!
Computers and handheld devices slow down every day. You can rejuvenate your smartphone/desktop just as fast and give them the occasional upgrade to keep or exceed that new speed feeling.
Electric cars are in the news again in an attempt to make us feel guilty about recycling our petrol cars for another year. Replacing an existing car with a new car creates more carbon dioxide than running your existing car for another 15 years. Do you really need a new car?
Openbiblio is free open source software and can run on very low cost Web hosts. This could be the lowest cost first option for your library when you have the right software skills on your team.
Programming in C is difficult and the reward is fast execution of the code. For someone learning C, there is also the reward of excellent brain cell exercise.
Solar power is difficult and expensive but is the better choice for many uses. In sunny Australia, solar power is close to the default power source with power storage the real sticking point. Hydroelectric storage, the current best storage, is coming to towns near you.
Timeshift is promoted as a way to recover files for a broken system or user directory. I use Timeshift to backup everything so I can restore anything.