Time Share is also known as “multipropiedad” and Shared property is known as “propiedad compartida”

If you want to buy an apartment under a “time sharing” agreement, you should know that you are NOT the owner of this property. In fact, the owner sells rights of use, known as “weeks”; generally there could be as much as 51 'weeks' sold for one apartment. You are only entitled to use this apartment for 'your' week, and in some cases you could “exchange” this week for another week in another resort, in an another place.
Unfortunately, you have many obligations: first of all, you will pay (high) community fees (which includes management cost, maintenance, etc.); if you forget to pay (for example) three months of your charges, you will simply lose everything: the promoter can take back your holiday week.
Some holidaymakers complained because they could not get in to 'their' apartment that was initially shown and written in the contract.  
Some people are very happy with the system, but it is very difficult to “sell” a time share week.
If you are  stopped by someone in the street telling you that you can win “something” and they invite you to go to their office, just be careful. Do not sign any contract under pressure: if it is a bargain, it will still be a bargain next week. And the Spanish law says that, even if you have signed a contract, you can ask to cancel everything within one week (in writing).

A different agreement is “shared property”.
In this case, you are the owner, but not the only one. Generally, in the case of inheritance, each child will own a part of the family house.
In the case of “shared property”, some people voluntarily decide to buy a house or apartment together. There will only be a limited number of owners, for example, four of the same property.
You will be able to decide together when you will stay in your new property, and one of the owners must attend the AGM (general meeting) of owners, if any, to directly defend your interests.

Stéphane MERCIER, economist and tax expert. Expertos de Tenerife S.L.