If you live in one of the many places in London (particularly south)
where there are NR stations and local shops can't top up Oyster, you
have little choice but to get a paper season ticket. You might have an
Oyster which you put prepay on when you get the chance, near work in
central London say, but you wouldn't be able to put your travelcard on
it on the morning when you needed to renew.

Why not? Assuming you live within the Travelcard Area, there's nothing
to stop you from getting a Weekly or longer Travelcard on Oyster and
renewing it in advance (as your Oyster has three slots for Season
Tickets).

I live in Edmonton, North London. My nearest Underground stations are
Turnpike Lane - Southgate (inclusive) on the Piccadilly Line or Seven
Sisters on the Victoria Line. Admittedly, I do have several Oyster
."Ticket Stops" nearby, but I opt to renew my Monthly at a convenient
Underground Station about a week before it runs out. Problem solved.

I was in Twickenham recently, and could not find anywhere that could
top up an Oyster.

Your lack of planning is no ones fault but your own. A quick visit or call
to TfL and you would have discovered there are loads of places to top up in
Twickenham.

I D NEWS 101 WHITTON ROAD TWICKENHAM TW1 1BZ

M G NEWS 385 ST MARGARETS ROAD TWICKENHAM TW1 1PP

NIKE 151 ST MARGARET'S ROAD TWICKENHAM TW1 1RG

HND SELF SERVICE 408 RICHMOND ROAD TWICKENHAM TW1 2EB

A.J. NEWS 361 RICHMOND ROAD TWICKENHAM TW1 2EJ

CROWN NEWSAGENTS 183 RICHMOND ROAD TWICKENHAM TW1 2NJ

THAMES NEWSAGENTS 66 RICHMOND ROAD TWICKENHAM TW1 3BE

MARALYN COLES 44 YORK STREET TWICKENHAM TW1 3BZ

MODI'S N/A OFF LIC 47 KINGS STREET PARADE TWICKENHAM TW1 3SG

SAGGARSONS 157 HEATH ROAD TWICKENHAM TW1 4BH

LONDIS - DHILLONS 136 HEATH ROAD TWICKENHAM TW1 4BN

ANGELS NEWS 20 STAINES ROAD TWICKENHAM TW2 5AH

M.S NEWSAGENTS 326 STAINES ROAD TWICKENHAM TW2 5AT

MEET & DEEP NEWSAGENTS 34 HAMPTON ROAD TWICKENHAM TW2 5QB

NEWSAGENTS 237 POWDERMILL LANE TWICKENHAM TW2 6DH

TEENS NEWS 300 NELSON ROAD TWICKENHAM TW2 7AD

NEWSAGENT 82 NELSON ROAD TWICKENHAM TW2 7AY