One of the statistics I regularly keep!!
It depends of course on 2 interlinked aspects
a. Your style of travel - resulting in a "cost per day"
b. Your speed of travel- resulting in "days per WHS"Regarding "cost per day".
I suspect we each think we travel without "wasting money" but I suspect also that we will each be shocked to see how much/little some of us actually spend! Many years ago I did my share of real rock bottom travel – sleeping out, hitching, overnight bus to avoid hotels, cheapest possible meals etc and we have had people travelling like that reporting on this site. Nowadays I would describe my travel as "cost conscious comfortable". Mrs Solivagant has pushed me up market a bit on hotels which are usually 3***, sometimes 2** or just "best available". On the other hand we prefer to rent cars and if necessary in a particular country will do so with a paid driver!
Travelling as a twosome reduces many of the costs per head - sharing of car rental/petrol and cheaper double rooms. Another factor in the cost per day is how long one's trips are. All the costs/elapsed times I quote below are "door to door" and just leaving home costs money with drive to A/p, car parking there and flights of course. In general the more separate trips you take the higher the %age of such overheads within the total cost.
Organised trips taken with commercial companies are also going to push up the cost per day in most cases – especially if those companies are centred in Europe/US. We try as far as possible to travel either independently or using a local travel company if we judge that local pre-organisation is necessary to be sure of fitting in everything we want to see.
Then of course it depends on the cost getting to the countries you visit and the cost of living when there (and "exchange rate effects"). In fact, leaving the "extremes" of the World to one side the variation in long haul flight costs isn't a major aspect of the total trip cost nowadays and many of the furthest countries from UK are relatively "cheap" to live in. On the other hand the closer European countries are cheap to get to but with relatively expensive cost of living! Visas can also push up the cost – we recently spent c £300 each on getting visas for Iran! Some nationalities will have to get many more visas than others. Where one lives will also have an impact. Those living in the European "heartland" and using their own car to visit a large number of them could expect to spend less per WHS than those residing elsewhere - though perhaps they should count vehicle "depreciation"!Regarding "days per WHS".
The "slower" your means of transport the fewer WHS you will see in a given time so, to some extent, it is a trade off with "cost per day". Then there is the extent of "targeting" of WHS - time spent seeing other things, relaxing etc will reduce the ratio. Then there is the effect of the number/closeness of WHS in the countries/areas being visited. Much of Europe is so packed with WHS that it is very easy to improve the "Days per WHS" but other countries will not be as easy. Cultural sites are usually a lot easier to pick up/see than Natural ones which often require at least a couple of days walking
Our travel style is "fast" with no relaxation time and reasonably "WHS targeted". We also pick up TWHS –which can be "money in the bank" as far as cost per WHS if any of them subsequently get inscribed (though I haven't counted such subsequent sites in my figures)! On the other hand many of our trips also include WHS already visited (also not counted) and that is another factor - if you can pick up ALL a country's WHS in 1 go then you will reduce the cost but if you have to keep going back either because you missed them or (as is mainly our case) you visited before the country had any/many WHS, then the number of new WHS per trip is going to be reduced.So - what are our figures?
My planning datum line for holidays in recent years is £100 per day per person all in. I then work up and down from that taking into account the reality of the country and the means of travel available. In my mind I need to justify any increase above that but, if you want to go to E.g PNG, then it is just going to cost you a lot of money (and only 1 WHS as well - which we didn't see!!). In fact recent trips to Europe have come in somewhat under that - including an amazing 21 day trip with rent-a-car in Spain at £51pppd!! On the other hand Germany a few years ago cost us as much per day (£135) as Iran as we spent a week at the "opera. These things tend to "average out". Most of our trips are in the 1 – 3 week range which tends to increase the "overhead costs" element.
My recent (since 2012) actual datum for "Days per new WHS" is 1.6. This is taken across our most recent 14 trips. These have included a lot of European trips with plenty of WHS which improve the figure but also others to e.g. NE India with very few, which reduce them (as did the above mentioned German trip). I will concede however that this "set" of trips doesn't include any "really" hard/expensive to reach WHS but I wouldn't have thought that it was an atypical set and could be repeated a number of times across different countries and WHS to cover a large %age of all WHS at similar speed and cost. It is heavily "Cultural site"oriented but also includes some Natural sites e.g In NE India which accounted for several days each. The figure would also be closer to 1 per day if I included our "previously seen WHS". So what is our overall cost per WHS?
Putting the above 2 figures together produces a figure of £143 per WHS.
Here is the raw data per trip across the 14 tripshttp://www.worldheritagesite.org/profiles/CostandWHSpertrip1.xls