Exact phrases in the title tag are (imho) a no no on longer phrases - say 4 or 5 words - if the competition is high. Now thats kind of a guess just browsing the serps. If you search a long string with quotes (a popular one) then get a feel for how many titles show in the serp - and compare that to a search without quotes for the same string you will generally not see very many of those full strings in there for high volume searches where normal distribution dictates a proportionally high volume of pages aswell (generally).
If however theres a high volume of searches but a low number of pages - quite rare - you may see the longer exact match strings in the serp without quotes.
I dont know the science behind this.
Lorel - your crawl rate will vary on a number of factors. My guess at three factors would be as follows.
1. Your PageRank/TrustRank value - a higher value would cause a more frequent crawl.
2. Rate of inbound link aquisition - at all levels from 1 link per week to 1 link per hour - new links I suspect and the volume thereof would be an indicator to goofle used in determining an appropriate crawl frequency.
3. Rate of page changes - I (again suspect) that a website which is updated every day with new content would (eventually) gain an increased crawl frequency.
All of the above is easily computed real-time(ish) so variants in any or all of the above (say a drop in rate of page changes for one) could affect the crawl frequency.
There will be knobs and switches for sure and many other factors probably.
Im in a good position at the moment to check point c) above on one site of mine as I am adding new content each time I get a cache update. In theory - the cache updates should become more frequent - and thus to make them even more frequent I would add content more frequently and so on. Eventually - again in theory - I may get a cache update daily or so. As long as keep up!
Can anyone add to the above?