Budget Tube Integrated? + Tube related questions

Hi Gurus,

I'm building my first hifi for a new apartment I will be moving into. The system will go into the living room (about 11 by 11ft) and will be used for music mostly and TV/movies occasionally.

I'm keen on a Tube integrated, as I would love a natural, warm sound. I love Jazz and I hear that tubes and vinyl are a match made in heaven (looking to build a vinyl setup in the near future but for now just an Airport Express with lossless files).

Unfortunately my budget is about 500-600 for the amp, and so far only Jolida's offerings seem to be in the ballpark (excluding Chinese amps like Qinpu - are these any good by the way?) Cheaper tubes also tend to have lower outputs, around 20w into 8ohms for the Jolida FX10.

Is it absolutely necessary to get high sensitivity speakers in such a case? Or would these amps be ok driving regular budget bookshelves (like the Wharfedale Diamonds or PSB Alpha/Image, Paradigm monitors etc.)? Since my room is pretty tiny, I was wondering if it'd be ok?

Or should I totally forgo tubes at this price range? Some have suggested that tubes in the below 1000 mark generally aren't worth the bother.

Also I'll be running the setup for several hours a day - including background listening. Is this detrimental for a tube setup? Do I have to replace tubes frequently with such usage?