For a webmaster, every CMS is a challenge, every project needs to succeed and every backend issues needs a solution. But what if you are working on these for another person / team ? Do you think that is where a webmaster would put his 100 % effort ?
I often feel that unless you pay them a premium it is hard to get the same level of dedication from a third party.
Unless you compensate them well, it is hard to believe that they will do their best. Not everyone falls for money. Different people, different needs. If someone is truly deserving, I will offer my services free of charge. There are a lot of people with enough empathy to help you out.
But in most cases, money works. I would suggest a proper backup procedure before you let someone on your server.