I agree with applying for a visitor visa in advance. My first trip to visit my now hubby was to be for 5 months, in 2004. I called the British Consulate in Chicago on two occasions with my concerns, and was assured I wouldn't need one because I was going for under 6 months. I had a job to go back to, but silly and unaware as I was then, I didn't have that documented. A simple note from the boss on company letterhead would have saved a bit of heartache. I had proof of what I had in my bank account, and it was more than enough for my financial needs for the time. I also had a return ticket. My gut instinct to go ahead and apply for the visitor visa would have saved immense heartache. I was refused entry but she allowed me in short term, so I was there 15 days. It didn't make sense to allow me in denied, because if she truly thought I was trying to sneak in, as she said she did, I could have easily disappeared in that time. But, that wasn't my intention. Then. after hubs came 2 months later and we were married, he moved to the States. The next visit to his family, I had to get an entry clearance visa for the two weeks we were going.
That taught me the lesson it is better to be overly prepared and perhaps pay out money you wouldn't have had to, to make life easier. With the rules being tighter now, and no job to return to, making all efforts to show you intend to return is your best bet.