$800, for a 5 year extended warranty is not bad. But also depends on the RV. Is this a $10,000 TT or a $30,000 TT?
When it comes to extended warranties, you need to be the one to make the decision and not necessarily listen to others. Several things come into mind that might make one to decide on whether to purchase a warranty or not. One is budget. Will you be ok coming out of pocket of up to around a $1000 at a time? Call a service center and ask what the cost to replace a refrigerator is. Cost of refrigerator plus the labor. Is that something you can easily come up with? If so, then a warranty may not be for you. If you may not have the money right now, but have no problem having a broke items in your TT until you can get it fixed, then you may not want a warranty. Or if you are able to fix things yourself and have the time.
But if you want to be able to get things fixed and not have to worry about things, like time or the cost, then it may be for you. Personally, we bought them on the TT we had and on the MH we currently have. For us, it's peace of mind. We both work full time. Getting off work to go camping is bad enough. Having to deal with something broken and even causing us not to be able to go camping is not worth it. When spending as much as we have on our units, what's another thousand or so? It's like people buying big 5th wheels and 1 ton trucks. Then they complain about the price of gas and won't go camping (not at the low cost of gas now, but a year or two ago they were doing this). RV's (whether towables or driveables) are gonna cost you above the purchase price. People need to take that into consideration when purchasing. You have gas/maintenance/registration/insurance/winterizing/etc....Then you have the possibility of repair.
$800/5 years = $160 a year. Or $13.33 (2 combo meals at McDonalds or 2-3 coffees at Starbucks) a month over the 5 years. How much money do you spend monthly that you could not spend, but put it towards the warranty? It cracks me up. People will shutter at spending $1000 (one time) or so for a 5 year warranty, but have no problem spending a two to three thousand dollars (or more) a years on things like cigarettes. Just like those who smoke that it's no one else's business, it's no one else's business of whether you get the warranty or not. Spend you r money on what you are comfortable with and don't worry what others think.