Technical Advice Please re Dual SIM card dual standby

[Anonymous]

I want to buy a simple (and inexpensive) mobile phone for someone who is even less well-informed that I am.  One that I think, prima facie, would be suitable is a HD 3G Mini S5 which is said to have  "Dual SIM card dual standby".  Although I have Googled this I am none the wiser.  What does it mean in practice?  Will the phone have to have 2 SIM cards inserted, and if that is so would that mean 2 tariffs?  Would there be any appreciable negative impact on normal usage if only 1 SIM is inserted? 

Have I given enough information to establish what size of SIM card(s) would be needed?

Sorry if these are too silly questions.

[Anonymous]

I will be interested to know how you get on @Gerry. I won't lie, I don't want to spend £25 at this time on a dual adapter when I have a spare S4 to put the EE sim in.

Also as I expect to be changing networks in June I might just wait and see. ....

[Anonymous]

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@Anonymous wrote:
@I will be interested to know how you get on @Anonymous.

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Hi @Anonymous   I have just noticed that there was a silly typo in one of my earlier posts.  I meant to say that I had decided not to buy a dual sim model for the person in question as he could not be relied upon to use it with care (and would probably throw a tantrum if  a dual Sim model had only one Sim available).  So I will look for something less complicated for him (and for me).