5 mins a day is better then 1 hour per week....

Sensei discusses this a lot. Rather than leave your keiko to a one week session, allocating 5-10 mins per day of practising kihon (and basics alike) will develop fluency and strengthen physio-neurological pathways. This has been proved in various studies, not just with budo, but basketball, golf etc. I remember when I started keiko with Sensei and I told him of my circumstances with work and the inability to train everyday. He simply advised me to visualise my own keiko, utilise imagery, shadow train and even practise weapons empty handed with the spirit of holding one. This I did the next day at work, taking the stairs and climbing up to the top floor of the building which housed the office I was teaching english at. Taking off my shirt and tie, rolling my trousers up (it was summer mind you),I began going through the motions of 'my' personal keiko. This I still do (as other dojo-cho do) unconsciously and in some cases anywhere, regardless of the interest it might attract from gawking bystanders. It does however serve to keep the body loose, limber and fluid. Sensei also added at this time that one should also advance in their 'shadow training' to the point that they can do it as if one is holding a weapon, like a rokushaku bo for instance. Via my own personal experiential research the more one trains with a live or real weapon, the easier this becomes.
See how you go and give me feedback.
Cheers!