I'm also a fan of doing a light tune every ski day or almost every ski day. When done often it is easy to get edges sharp, sometimes it only needs a few swipes with a diamond stone. I've noticed that the plastic diamond stones bend a little, so when using a diamond stone with an edge guide, I usually clamp a file over the top to keep it flat. If the edge needs a bit more work, a fine or very fine file is used. I have several files with different cuts that I use depending on how bad the edges are.
I also think that the bases stay better if they are waxed often. A good brush with a good steel cleaning brush, then a wax can also be done fairly quickly. Get a wax iron that feels heavy - there are some cheap ones that have no substance and don't work well.
I usually rub the wax on the base and then iron, rather than drip it on. This saves $, especially if you treat your skis to some high flouro wax.
Keeping your plastic scraper (for scraping wax) sharp is important. Use 220 grit sandpaper to keep your plastic scraper sharp. Just lay the sandpaper on a flat surface and sand the edge of the scraper with back and forth movements while holding it perpendicular to the paper. Do this often (e.g. every ski base that you scrape) as a sharp scraper works a whole lot better than a dull scraper.
as to the OP questions,
1. Unless I need base repair and a complete stone grind, I believe that I do a much better job tuning than any shop, with one exception, but he is had been a ski tech for world cup skiers. Having said that, I probably do as good on the edges as his shop. Both my kids are racers and I have done more tunes than I care to count over the last 12 years and I have had to get efficient (sometimes did 6 to 8 pairs a night). Now my kids do their own skis. Although they do a good job, they are slow.
2. Invest in a tuning kit.
I enjoy tuning skis. Some good music and a bit of scotch makes the whole process quite relaxing